project_muse_61837-full

  • Task Overview: This project aims to enhance user engagement by implementing dynamic content features.

  • Key Deliverables:

    • Development of a user feedback system to tailor content offerings.

    • Integration of AI technologies for personalized recommendations.

    • Engagement metrics report to assess the impact of new features. Creation of an updated user interface to enhance navigation and accessibility. Improved marketing strategies based on user insights to increase outreach and user retention.

1 The Science in Social Science
1.1 Introduction

This book focuses on research design in the social sciences, aiming to produce valid inferences about social and political life. While primarily focused on political science, the principles extend to other disciplines like sociology, anthropology, economics, psychology, and interdisciplinary fields such as legal evidence and education research. The core objective is practical: to guide scholars on how to formulate research questions and designs that lead to valid descriptive and causal inferences, focusing on the essential logic underlying all social scientific inquiry.

1.1.1 Two Styles of Research, One Logic of Inference

Despite conventional distinctions, quantitative and qualitative research traditions share a unified logic of inference, with their differences being primarily stylistic or technical. Quantitative research relies on numbers, statistical methods, numerical measurements, seeks general descriptions and causal hypotheses, and prioritizes replicability. Qualitative research, conversely, does not use numerical measurements; it often focuses on a small number of cases, employs intensive interviews or in-depth historical analysis, is discursive, and aims for comprehensive accounts of events or units. Both styles can yield vast amounts of information.

Historically, debates between case studies and statistical studies, or “scientific” quantitative methods versus “historical” qualitative investigations, have bifurcated the social sciences. However, this book argues that these differences are superficial. All robust research derives from the same underlying logic of inference, allowing both quantitative and qualitative approaches to be systematic and scientific. The best research often integrates elements from both, as exemplified by studies like Lisa L. Martin’s “Coercive Cooperation” and Robert D. Putnam’s “Making Democracy Work,” which combine quantitative analysis with detailed case studies.

The rules of scientific inference discussed are relevant to all research that seeks to uncover facts about the real world, distinguishing social science from casual observation. This approach assumes a partial and imperfect knowability of the external world, acknowledging that certainty is unattainable. Nevertheless, strict adherence to these rules can enhance the reliability, validity, and honesty of conclusions. The aim is to foster disciplined thought rather than rigid dogma, recognizing that research involves the imperfect application of theoretical standards to inherently imperfect designs and data.

1.1.2 Defining Scientific Research in the Social Sciences

“Scientific research,” as defined here, represents an ideal that actual quantitative or qualitative studies approximate. Regardless of style, scientific research design is characterized by four key features:

  1. The goal is inference: Scientific research aims to make descriptive or explanatory inferences based on empirical information, reaching conclusions that extend beyond the immediate data observations. This includes descriptive inference (learning about unobserved facts from observations) and causal inference (learning about causal effects).

  2. The procedures are public: Scientific research employs explicit, codified, and public methods for data generation and analysis, making its reliability assessable. This transparency allows for judgment, learning, and replication by the scholarly community, contrasting with research that keeps its methods implicit.

  3. The conclusions are uncertain: Inference is an imperfect process, and achieving perfectly certain conclusions from uncertain data is impossible. Acknowledging and reporting uncertainty is central to all scientific knowledge. Without a reasonable estimate of uncertainty, real-world descriptions or causal inferences are uninterpretable.

  4. The content is the method: The essence of “science” lies in its methods and rules of inference, not its subject matter. These methods are applicable across virtually any field of study, as “the unity of all science consists alone in its method, not in its material.”

These characteristics imply that science is a social enterprise. Researchers operate within limitations, and errors are inevitable; however, the public and shared nature of scientific inquiry means that errors are likely to be identified and corrected by the community. Work contributes significantly when it addresses scholarly concerns and uses public, rule-consistent methods to draw inferences.

1.1.3 Science and Complexity

Social science attempts to understand social situations, which are often perceived as complex. However, this perceived complexity is partially dependent on the ability to simplify reality through coherent specification of outcomes and explanatory variables, which in turn relates to the state of existing theory. Scientific methods are valuable for both simple and complex events; while complexity may increase uncertainty, it does not diminish the scientific nature of the inquiry. The greatest benefits of scientific inference rules are often realized precisely when data are limited, tools are flawed, and relationships are uncertain.

Even seemingly unique and complex events, such as the collapse of the Roman Empire or the extinction of the dinosaurs, can be studied scientifically. Approaches include seeking generalizations by conceptualizing cases as members of a class, or engaging in counterfactual analysis—mentally constructing altered courses of events by modifying conditions. For example, the Alvarez hypothesis for dinosaur extinction posits a cosmic collision, which has observable implications like the presence of iridium in geological layers, allowing scientific testing even for a unique event.

Ultimately, scientific generalizations are useful for unusual events if they yield observable implications that can be empirically evaluated. A hypothesis is not considered certain until it has undergone demanding empirical tests and ideally predicts previously unobserved, “new facts.” Research design, especially in improving theory, data collection, and data utilization, remains crucial even for highly complex phenomena. Collecting data on as many observable implications of a theory as possible enhances the study.

1.2 MAJOR COMPONENTS OF RESEARCH DESIGN

Effective social science research is a creative process within a structured scientific inquiry. While flexibility in research is vital for overturning old views and posing new questions, all revisions must adhere to explicit procedures consistent with the rules of inference. Research often involves an iterative process where initial designs and collected data reveal imperfect fits, requiring adjustments to research questions or theories.

The research design can be analytically broken down into four key components:

  1. The research question

  2. The theory

  3. The data

  4. The use of the data

These components are not necessarily developed in a linear order; for instance, qualitative researchers might start with data. Understanding each component helps researchers make informed compromises given practical constraints, maximizing the quality of their designs.

1.2.1 Improving Research Questions

Choosing a research topic often involves personal and idiosyncratic elements—“creative intuition” as Karl Popper suggested—with less formalized rules compared to specific research techniques like survey design or participant observation. While personal motivations for choosing a topic are valid, for a social science contribution, the methods and rules of inference will enhance the research design. From a scholarly perspective, personal reasons are neither necessary nor sufficient justifications.

Ideally, all social science research projects should satisfy two criteria to maximize their value to the scholarly community:

  1. ”Important” in the real world: The question should be consequential for political, social, or economic life, significantly affecting many people or aiding in understanding and predicting harmful/beneficial events. This is largely a societal judgment.

  2. Specific contribution to an identifiable scholarly literature: The project should enhance the collective ability to construct verified scientific explanations, whether through descriptive inference, critical observation, or historical summarization, which are prerequisites for explanation.

While social scientists have an abundance of significant real-world issues (e.g., wars, economic privation) to study, effective tools for understanding them are scarce. Brilliant insights alone are not sufficient; all hypotheses require empirical evaluation to contribute to knowledge. Making a scholarly contribution involves explicitly situating the research within existing literature to grasp the “state of the art,” avoid duplication, and ensure relevance to other scholars. Contributions can take various forms:

  1. Investigating important hypotheses that lack systematic study.

  2. Examining accepted hypotheses suspected to be false or inadequately confirmed.

  3. Resolving or providing further evidence for controversies in the literature.

  4. Illuminating or evaluating unquestioned assumptions.

  5. Addressing overlooked important topics with systematic study.

  6. Applying existing theories or evidence from one literature to another to solve an apparently unrelated problem.

Balancing these two criteria—real-world importance and scholarly contribution—is crucial. Overemphasis on literature can lead to politically insignificant questions, while neglecting scholarly frameworks can result in careless work. The best research strives to bridge both, enhancing real-world understanding through scientific methods and contributing to theoretical advancements. The research design process should always aim to meet both criteria, regardless of the starting point.

1.2.2 Improving Theory

A social science theory is a precise, reasoned speculation about a research question’s answer, explaining why the proposed answer is correct and implying specific hypotheses. It must be consistent with prior evidence. While theory development is often presented as the first research step, it usually requires some initial knowledge of prior work and data.

To improve a theory, especially before data analysis, consider these guidelines:

  1. Falsifiability: Choose theories that could be wrong. A theory must be able to be disproven by evidence; if no such evidence can be conceived, it’s not a testable theory.

  2. Observable Implications: Design theories to generate as many observable implications as possible. This allows for more varied tests with diverse data, increasing the theory’s risk of falsification and providing stronger evidence if it withstands tests.

  3. Concreteness: State theories and hypotheses precisely to avoid obfuscation. Specific predictions are more easily falsified and thus superior.

The principle of parsimony (that simple theories have higher prior probabilities) is sometimes debated. It implies an assumption about the simplicity of the world, which may be appropriate in some fields (like physics) but not universally. It is recommended only if there is prior knowledge suggesting the world under study is indeed simple; otherwise, theories should be as complex as the evidence dictates.

If data has already been collected, improving the theory requires caution. Ad hoc adjustments to a theory based on existing data, though seemingly plausible, can be misleading. Generally, it is acceptable to make a theory less restrictive (applying to a broader range of phenomena) after observing data, as this increases its exposure to falsification. However, making a theory more restrictive (narrowing its scope to fit observed exceptions) without collecting new data to test the modified version is generally inappropriate. Such modifications turn falsifications into spurious generalizations without new supporting evidence.

If new data cannot be collected, admitting that the original theory is wrong is often the best course; negative findings can be very valuable. Researchers can then suggest additional conditions or alternative theories for future research, acknowledging the uncertainty of such speculations. Pilot projects are highly beneficial, as preliminary data collection can lead to theory or question adjustments, allowing new data to be collected to test the revised theory, thus avoiding the problem of using the same data for both theory generation and testing.

1.2.3 Improving Data Quality

“Data” refers to systematically collected information, whether qualitative or quantitative. Regardless of whether data is collected for a specific theory or broader exploration, certain rules enhance its quality:

  1. Record and Report the Data Generation Process: This is the most crucial guideline. Without explicit information on how data were generated (e.g., sampling methods, specific questions, case selection rules), determining the reliability of inferences is impossible. Transparency ensures valid descriptive or causal inferences.

  2. Collect Data on Many Observable Implications: To comprehensively evaluate a theory, gather data on as many of its observable implications as possible, across diverse contexts. Each additional consistent implication strengthens the theory.

    • This includes collecting more observations on the same dependent variable (e.g., disaggregating time or geographic areas) or recording additional dependent variables (e.g., for deterrence theory, also examining if threats themselves are deterred).

    • Testing similar theories in analogous situations (e.g., deterrence in international politics compared to oligopolistic firms) can also provide valuable insights, even if direct applicability remains uncertain.

  3. Maximize the Validity of Our Measurements: Ensure that what is being measured truly reflects what is intended. Validity is best achieved by adhering closely to observable data and avoiding reliance on unobserved or unmeasurable concepts.

  4. Ensure Data-Collection Methods are Reliable: Reliability means that the same procedure, applied consistently, will produce the same measure given no change in the object being measured. Explicit procedures enable different researchers to obtain identical results, enhancing comparability (e.g., using multiple coders for qualitative data).

  5. Replicability of All Data and Analyses: Research outputs should be detailed enough for another researcher to duplicate the data collection and trace the logic of conclusions. Replicability is vital for evaluating procedures and methods, even if actual replication doesn't occur. For quantitative research, this often means replicating the analysis from the same dataset. For qualitative research, it involves providing sufficient source information (footnotes, bibliographic essays) and, where possible, allowing access to raw data like field notes or interviews. While perfect replication is often impossible (e.g., in historical or observational studies), the commitment to transparency and access promotes scientific rigor, as exemplified by projects like the multi-decade replication of the “Middletown” studies.

1 The Science in Social Science

1.1 Introduction

This book focuses on research design in the social sciences, aiming to produce valid inferences about social and political life. While primarily focused on political science, the principles extend to other disciplines like sociology, anthropology, economics, psychology, and interdisciplinary fields such as legal evidence and education research. The core objective is practical: to guide scholars on how to formulate research questions and designs that lead to valid descriptive and causal inferences, focusing on the essential logic underlying all social scientific inquiry.

1.1.1 Two Styles of Research, One Logic of Inference

Despite conventional distinctions, quantitative and qualitative research traditions share a unified logic of inference, with their differences being primarily stylistic or technical. Quantitative research relies on numbers, statistical methods, numerical measurements, seeks general descriptions and causal hypotheses, and prioritizes replicability. Qualitative research, conversely, does not use numerical measurements; it often focuses on a small number of cases, employs intensive interviews or in-depth historical analysis, is discursive, and aims for comprehensive accounts of events or units. Both styles can yield vast amounts of information.

Historically, debates between case studies and statistical studies, or “scientific” quantitative methods versus “historical” qualitative investigations, have bifurcated the social sciences. However, this book argues that these differences are superficial. All robust research derives from the same underlying logic of inference, allowing both quantitative and qualitative approaches to be systematic and scientific. The best research often integrates elements from both, as exemplified by studies like Lisa L. Martin’s “Coercive Cooperation” and Robert D. Putnam’s “Making Democracy Work,” which combine quantitative analysis with detailed case studies.

The rules of scientific inference discussed are relevant to all research that seeks to uncover facts about the real world, distinguishing social science from casual observation. This approach assumes a partial and imperfect knowability of the external world, acknowledging that certainty is unattainable. Nevertheless, strict adherence to these rules can enhance the reliability, validity, and honesty of conclusions. The aim is to foster disciplined thought rather than rigid dogma, recognizing that research involves the imperfect application of theoretical standards to inherently imperfect designs and data.

1.1.2 Defining Scientific Research in the Social Sciences

“Scientific research,” as defined here, represents an ideal that actual quantitative or qualitative studies approximate. Regardless of style, scientific research design is characterized by four key features:

  1. The goal is inference: Scientific research aims to make descriptive or explanatory inferences based on empirical information, reaching conclusions that extend beyond the immediate data observations. This includes descriptive inference (learning about unobserved facts from observations) and causal inference (learning about causal effects).

  2. The procedures are public: Scientific research employs explicit, codified, and public methods for data generation and analysis, making its reliability assessable. This transparency allows for judgment, learning, and replication by the scholarly community, contrasting with research that keeps its methods implicit.

  3. The conclusions are uncertain: Inference is an imperfect process, and achieving perfectly certain conclusions from uncertain data is impossible. Acknowledging and reporting uncertainty is central to all scientific knowledge. Without a reasonable estimate of uncertainty, real-world descriptions or causal inferences are uninterpretable.

  4. The content is the method: The essence of “science” lies in its methods and rules of inference, not its subject matter. These methods are applicable across virtually any field of study, as “the unity of all science consists alone in its method, not in its material.”

These characteristics imply that science is a social enterprise. Researchers operate within limitations, and errors are inevitable; however, the public and shared nature of scientific inquiry means that errors are likely to be identified and corrected by the community. Work contributes significantly when it addresses scholarly concerns and uses public, rule-consistent methods to draw inferences.

1.1.3 Science and Complexity

Social science attempts to understand social situations, which are often perceived as complex. However, this perceived complexity is partially dependent on the ability to simplify reality through coherent specification of outcomes and explanatory variables, which in turn relates to the state of existing theory. Scientific methods are valuable for both simple and complex events; while complexity may increase uncertainty, it does not diminish the scientific nature of the inquiry. The greatest benefits of scientific inference rules are often realized precisely when data are limited, tools are flawed, and relationships are uncertain.

Even seemingly unique and complex events, such as the collapse of the Roman Empire or the extinction of the dinosaurs, can be studied scientifically. Approaches include seeking generalizations by conceptualizing cases as members of a class, or engaging in counterfactual analysis—mentally constructing altered courses of events by modifying conditions. For example, the Alvarez hypothesis for dinosaur extinction posits a cosmic collision, which has observable implications like the presence of iridium in geological layers, allowing scientific testing even for a unique event.

Ultimately, scientific generalizations are useful for unusual events if they yield observable implications that can be empirically evaluated. A hypothesis is not considered certain until it has undergone demanding empirical tests and ideally predicts previously unobserved, “new facts.” Research design, especially in improving theory, data collection, and data utilization, remains crucial even for highly complex phenomena. Collecting data on as many observable implications of a theory as possible enhances the study.

1.2 MAJOR COMPONENTS OF RESEARCH DESIGN

Effective social science research is a creative process within a structured scientific inquiry. While flexibility in research is vital for overturning old views and posing new questions, all revisions must adhere to explicit procedures consistent with the rules of inference. Research often involves an iterative process where initial designs and collected data reveal imperfect fits, requiring adjustments to research questions or theories.

The research design can be analytically broken down into four key components:

  1. The research question

  2. The theory

  3. The data

  4. The use of the data

These components are not necessarily developed in a linear order; for instance, qualitative researchers might start with data. Understanding each component helps researchers make informed compromises given practical constraints, maximizing the quality of their designs.

1.2.1 Improving Research Questions

Choosing a research topic often involves personal and idiosyncratic elements—“creative intuition” as Karl Popper suggested—with less formalized rules compared to specific research techniques like survey design or participant observation. While personal motivations for choosing a topic are valid, for a social science contribution, the methods and rules of inference will enhance the research design. From a scholarly perspective, personal reasons are neither necessary nor sufficient justifications.

Ideally, all social science research projects should satisfy two criteria to maximize their value to the scholarly community:

  1. ”Important” in the real world: The question should be consequential for political, social, or economic life, significantly affecting many people or aiding in understanding and predicting harmful/beneficial events. This is largely a societal judgment.

  2. Specific contribution to an identifiable scholarly literature: The project should enhance the collective ability to construct verified scientific explanations, whether through descriptive inference, critical observation, or historical summarization, which are prerequisites for explanation.

While social scientists have an abundance of significant real-world issues (e.g., wars, economic privation) to study, effective tools for understanding them are scarce. Brilliant insights alone are not sufficient; all hypotheses require empirical evaluation to contribute to knowledge. Making a scholarly contribution involves explicitly situating the research within existing literature to grasp the “state of the art,” avoid duplication, and ensure relevance to other scholars. Contributions can take various forms:

  1. Investigating important hypotheses that lack systematic study.

  2. Examining accepted hypotheses suspected to be false or inadequately confirmed.

  3. Resolving or providing further evidence for controversies in the literature.

  4. Illuminating or evaluating unquestioned assumptions.

  5. Addressing overlooked important topics with systematic study.

  6. Applying existing theories or evidence from one literature to another to solve an apparently unrelated problem.

Balancing these two criteria—real-world importance and scholarly contribution—is crucial. Overemphasis on literature can lead to politically insignificant questions, while neglecting scholarly frameworks can result in careless work. The best research strives to bridge both, enhancing real-world understanding through scientific methods and contributing to theoretical advancements. The research design process should always aim to meet both criteria, regardless of the starting point.

1.2.2 Improving Theory

A social science theory is a precise, reasoned speculation about a research question’s answer, explaining why the proposed answer is correct and implying specific hypotheses. It must be consistent with prior evidence. While theory development is often presented as the first research step, it usually requires some initial knowledge of prior work and data.

To improve a theory, especially before data analysis, consider these guidelines:

  1. Falsifiability: Choose theories that could be wrong. A theory must be able to be disproven by evidence; if no such evidence can be conceived, it’s not a testable theory.

  2. Observable Implications: Design theories to generate as many observable implications as possible. This allows for more varied tests with diverse data, increasing the theory’s risk of falsification and providing stronger evidence if it withstands tests.

  3. Concreteness: State theories and hypotheses precisely to avoid obfuscation. Specific predictions are more easily falsified and thus superior.

The principle of parsimony (that simple theories have higher prior probabilities) is sometimes debated. It implies an assumption about the simplicity of the world, which may be appropriate in some fields (like physics) but not universally. It is recommended only if there is prior knowledge suggesting the world under study is indeed simple; otherwise, theories should be as complex as the evidence dictates.

If data has already been collected, improving the theory requires caution. Ad hoc adjustments to a theory based on existing data, though seemingly plausible, can be misleading. Generally, it is acceptable to make a theory less restrictive (applying to a broader range of phenomena) after observing data, as this increases its exposure to falsification. However, making a theory more restrictive (narrowing its scope to fit observed exceptions) without collecting new data to test the modified version is generally inappropriate. Such modifications turn falsifications into spurious generalizations without new supporting evidence.

If new data cannot be collected, admitting that the original theory is wrong is often the best course; negative findings can be very valuable. Researchers can then suggest additional conditions or alternative theories for future research, acknowledging the uncertainty of such speculations. Pilot projects are highly beneficial, as preliminary data collection can lead to theory or question adjustments, allowing new data to be collected to test the revised theory, thus avoiding the problem of using the same data for both theory generation and testing.

1.2.3 Improving Data Quality

“Data” refers to systematically collected information, whether qualitative or quantitative. Regardless of whether data is collected for a specific theory or broader exploration, certain rules enhance its quality:

  1. Record and Report the Data Generation Process: This is the most crucial guideline. Without explicit information on how data were generated (e.g., sampling methods, specific questions, case selection rules), determining the reliability of inferences is impossible. Transparency ensures valid descriptive or causal inferences.

  2. Collect Data on Many Observable Implications: To comprehensively evaluate a theory, gather data on as many of its observable implications as possible, across diverse contexts. Each additional consistent implication strengthens the theory.

    • This includes collecting more observations on the same dependent variable (e.g., disaggregating time or geographic areas) or recording additional dependent variables (e.g., for deterrence theory, also examining if threats themselves are deterred).

    • Testing similar theories in analogous situations (e.g., deterrence in international politics compared to oligopolistic firms) can also provide valuable insights, even if direct applicability remains uncertain.

  3. Maximize the Validity of Our Measurements: Ensure that what is being measured truly reflects what is intended. Validity is best achieved by adhering closely to observable data and avoiding reliance on unobserved or unmeasurable concepts.

  4. Ensure Data-Collection Methods are Reliable: Reliability means that the same procedure, applied consistently, will produce the same measure given no change in the object being measured. Explicit procedures enable different researchers to obtain identical results, enhancing comparability (e.g., using multiple coders for qualitative data).

  5. Replicability of All Data and Analyses: Research outputs should be detailed enough for another researcher to duplicate the data collection and trace the logic of conclusions. Replicability is vital for evaluating procedures and methods, even if actual replication doesn't occur. For quantitative research, this often means replicating the analysis from the same dataset. For qualitative research, it involves providing sufficient source information (footnotes, bibliographic essays) and, where possible, allowing access to raw data like field notes or interviews. While perfect replication is often impossible (e.g., in historical or observational studies), the commitment to transparency and access promotes scientific rigor, as exemplified by projects like the multi-decade replication of the “Middletown” studies.

1.2.4 Improving the Use of Existing Data

While collecting new and better data is preferable, social scientists often have to make the best of existing, flawed data. Improving the use of previously collected data is a key aspect of inferential statistics and applies to qualitative research as well. Guidelines for this include:

  1. Generate Unbiased Inferences: Aim for inferences that are “unbiased,” meaning they are correct on average across many applications of the same methodology, even if individual applications are not perfectly accurate. This requires careful analysis of potential biases overlooked during data collection, such as selection bias (choosing observations that distort the population) or omitted variable bias (excluding relevant control variables).

  2. Maximize Efficiency: Utilize all available data and relevant information within it to maximize the information used for descriptive or causal inference. This can involve disaggregating data into smaller geographical units, even if associated with higher uncertainty, to extract more information from them.

1.3 THEMES OF THIS VOLUME

This section highlights four important themes in developing research designs.

1.3.1 Using Observable Implications to Connect Theory and Data

Every worthwhile theory must have observable implications that guide data collection and help distinguish relevant from irrelevant facts. Theory and empirical research must be tightly connected; empirical investigation is unsuccessful without theoretical guidance, and theory is meaningless without empirical implications. Researchers should constantly ask: “What are its observable implications?” for any theory, and “Are the observations relevant to the implications of our theory?” for any empirical investigation. Reliable social science conclusions require a strong connection between theory and data, forged by examining observable implications.

1.3.2 Maximizing Leverage

Maximizing leverage in social science means explaining as much as possible with as little information as possible. High leverage occurs when a complicated effect can be explained by a single variable or a few variables, or when many effects are explained by one or a few variables. Areas conventionally studied qualitatively often have low leverage, requiring many explanatory variables for little explanation, and thus research aims to increase it. Leverage can be increased by:

  1. Improving the theory to generate more observable implications.

  2. Improving data collection to observe and use more of these implications.

  3. Improving data use to extract more implications from existing data.

This is distinct from parsimony, which is an assumption about the world’s simplicity. Researchers should routinely list all possible observable implications of their hypothesis and test them in diverse contexts, including different units, levels of aggregation, and time periods. Even data from different levels of analysis can provide relevant information to evaluate a theory, as all observable implications contribute to its veracity.

1.3.3 Reporting Uncertainty

All knowledge and inference in both quantitative and qualitative research are inherently uncertain. Both measurement styles are error-prone, though their sources of error may differ. A significant problem in qualitative research is the pervasive failure to provide reasonable estimates of uncertainty. While valid inferences are possible even with limited evidence, researchers should avoid sweeping conclusions from weak data. It is crucial to always report a reasonable estimate of the degree of certainty in each inference. As Neustadt and May (1986:274) suggest, one effective way to gauge uncertainty is to ask, “How much of your own money would you wager on it?” while also considering, “At what odds?”

1.3.4 Thinking like a Social Scientist: Skepticism and Rival Hypotheses

Good social scientists approach causal inferences with skepticism, particularly regarding their own research. When a causal link is proposed (e.g., A causes B), a social scientist questions whether it is a true causal connection. This involves scrutinizing data accuracy (e.g., sampling, measurement consistency) and considering alternative explanations, such as other influential variables (e.g., other dietary factors, genetics, lifestyle choices) or the possibility of reversed causality. Causal inference is an iterative process of refining and testing conclusions through successive approximations, continuously seeking to move closer to accurate causal understanding. An example given is the correlation between less red meat consumption and fewer heart attacks in Japan compared to America, where a skeptical social scientist would question data accuracy, consider other variables, and ponder reverse causality.

1 The Science in Social Science

1.1 Introduction

This book focuses on research design in the social sciences, aiming to produce valid inferences about social and political life. While primarily focused on political science, the principles extend to other disciplines like sociology, anthropology, economics, psychology, and interdisciplinary fields such as legal evidence and education research. The core objective is practical: to guide scholars on how to formulate research questions and designs that lead to valid descriptive and causal inferences, focusing on the essential logic underlying all social scientific inquiry.

1.1.1 Two Styles of Research, One Logic of Inference

Despite conventional distinctions, quantitative and qualitative research traditions share a unified logic of inference, with their differences being primarily stylistic or technical. Quantitative research relies on numbers, statistical methods, numerical measurements, seeks general descriptions and causal hypotheses, and prioritizes replicability. Qualitative research, conversely, does not use numerical measurements; it often focuses on one or a small number of cases, employs intensive interviews or in-depth historical analysis, is discursive, and aims for comprehensive accounts of events or units. Both styles can yield vast amounts of information.

Historically, debates between case studies and statistical studies, or “scientific” quantitative methods versus “historical” qualitative investigations, have bifurcated the social sciences. However, this book argues that these differences are superficial. All robust research derives from the same underlying logic of inference, allowing both quantitative and qualitative approaches to be systematic and scientific. The best research often integrates elements from both, as exemplified by studies like Lisa L. Martin’s “Coercive Cooperation” and Robert D. Putnam’s “Making Democracy Work,” which combine quantitative analysis with detailed case studies.

The rules of scientific inference discussed are relevant to all research that seeks to uncover facts about the real world, distinguishing social science from casual observation. This approach assumes a partial and imperfect knowability of the external world, acknowledging that certainty is unattainable. Nevertheless, strict adherence to these rules can enhance the reliability, validity, and honesty of conclusions. The aim is to foster disciplined thought rather than rigid dogma, recognizing that research involves the imperfect application of theoretical standards to inherently imperfect designs and data.

1.1.2 Defining Scientific Research in the Social Sciences

“Scientific research,” as defined here, represents an ideal to which any actual quantitative or qualitative research, even the most careful, is only an approximation. Yet, we need a definition of good research, for which we use the word “scientific” as our descriptor. This word comes with many connotations that are unwarranted or inappropriate or downright incendiary for some qualitative researchers. Hence, we provide an explicit definition here. As should be clear, we do not regard quantitative research to be any more scientific than qualitative research. Good research, that is, scientific research, can be quantitative or qualitative in style. In design, however, scientific research has the following four characteristics:

  1. The goal is inference: Scientific research is designed to make descriptive or explanatory inferences on the basis of empirical information about the world. Careful descriptions of specific phenomena are often indispensable to scientific research, but the accumulation of facts alone is not sufficient. Facts can be collected (by qualitative or quantitative researchers) more or less systematically, and the former is obviously better than the latter, but our particular definition of science requires the additional step of attempting to infer beyond the immediate data to something broader that is not directly observed. That something may involve descriptive inference—using observations from the world to learn about other unobserved facts. Or that something may involve causal inference—learning about causal effects from the data observed. The domain of inference can be restricted in space and time—voting behavior in American elections since 1960, social movements in Eastern Europe since 1989—or it can be extensive—human behavior since the invention of agriculture. In either case, the key distinguishing mark of scientific research is the goal of making inferences that go beyond the particular observations collected.

  2. The procedures are public: Scientific research uses explicit, codified, and public methods to generate and analyze data whose reliability can therefore be assessed. Much social research in the qualitative style follows fewer precise rules of research procedure or of inference. As Robert K. Merton ([1949] 1968:71–72) put it, “The sociological analysis of qualitative data often resides in a private world of penetrating but unfathomable insights and ineffable understandings. . . . [However,] science . . . is public, not private.” Merton’s statement is not true of all qualitative researchers (and it is unfortunately still true of some quantitative analysts), but many proceed as if they had no method—sometimes as if the use of explicit methods would diminish their creativity. Nevertheless they cannot help but use some method. Somehow they observe phenomena, ask questions, infer information about the world from these observations, and make inferences about cause and effect. If the method and logic of a researcher’s observations and inferences are left implicit, the scholarly community has no way of judging the validity of what was done. We cannot evaluate the principles of selection that were used to record observations, the ways in which observations were processed, and the logic by which conclusions were drawn. We cannot learn from their methods or replicate their results. Such research is not a public act. Whether or not it makes good reading, it is not a contribution to social science. All methods—whether explicit or not—have limitations. The advantage of explicitness is that those limitations can be understood and, if possible, addressed. In addition, the methods can be taught and shared. This process allows research results to be compared across separate researchers and research projects studies to be replicated, and scholars to learn.

  3. The conclusions are uncertain: By definition, inference is an imperfect process. Its goal is to use quantitative or qualitative data to learn about the world that produced them. Reaching perfectly certain conclusions from uncertain data is obviously impossible. Indeed, uncertainty is a central aspect of all research and all knowledge about the world. Without a reasonable estimate of uncertainty, a description of the real world or an inference about a causal effect in the real world is uninterpretable. A researcher who fails to face the issue of uncertainty directly is either asserting that he or she knows everything perfectly or that he or she has no idea how certain or uncertain the results are. Either way, inferences without uncertainty estimates are not science as we define it.

  4. The content is the method: Finally, scientific research adheres to a set of rules of inference on which its validity depends. Explicating the most important rules is a major task of this book. The content of “science” is primarily the methods and rules, not the subject matter, since we can use these methods to study virtually anything. This point was recognized over a century ago when Karl Pearson (1892: 16) explained that “the field of science is unlimited; its material is endless; every group of natural phenomena, every phase of social life, every stage of past or present development is material for science. The unity of all science consists alone in its method, not in its material.”

These four features of science have a further implication: science at its best is a social enterprise. Every researcher or team of researchers labors under limitations of knowledge and insight, and mistakes are unavoidable, yet such errors will likely be pointed out by others. Understanding the social character of science can be liberating since it means that our work need not to be beyond criticism to make an important contribution—whether to the description of a problem or its conceptualization, to theory or to the evaluation of theory. As long as our work explicitly addresses (or attempts to redirect) the concerns of the community of scholars and uses public methods to arrive at inferences that are consistent with rules of science and the information at our disposal, it is likely to make a contribution. And the contribution of even a minor article is greater than that of the “great work” that stays forever in a desk drawer or within the confines of a computer.

1.1.3 Science and Complexity

Social science constitutes an attempt to make sense of social situations that we perceive as more or less complex. We need to recognize, however, that what we perceive as complexity is not entirely inherent in phenomena: the world is not naturally divided into simple and complex sets of events. On the contrary, the perceived complexity of a situation depends in part on how well we can simplify reality, and our capacity to simplify depends on whether we can specify outcomes and explanatory variables in a coherent way. Having more observations may assist us in this process but is usually insufficient. Thus “complexity” is partly conditional on the state of our theory. Scientific methods can be as valuable for intrinsically complex events as for simpler ones. Complexity is likely to make our inferences less certain but should not make them any less scientific. Uncertainty and limited data should not cause us to abandon scientific research. On the contrary: the biggest payoff for using the rules of scientific inference occurs precisely when data are limited, observation tools are flawed, measurements are unclear, and relationships are uncertain.

Consider some complex, and in some sense unique, events with enormous ramifications. The collapse of the Roman Empire, the French Revolution, the American Civil War, World War I, the Holocaust, and the reunification of Germany in 1990 are all examples of such events. These events seem to be the result of complex interactions of many forces whose conjuncture appears crucial to the event having taken place. That is, independently caused sequences of events and forces converged at a given place and time, their interaction appearing to bring about the events being observed (Hirschman 1970). Furthermore, it is often difficult to believe that these events were inevitable products of large-scale historical forces: some seem to have depended, in part, on idiosyncracies of personalities, institutions, or social movements. Indeed, from the perspective of our theories, chance often seems to have played a role: factors outside the scope of the theory provided crucial links in the sequences of events.

One way to understand such events is by seeking generalizations: conceptualizing each case as a member of a class of events about which meaningful generalizations can be made. This method often works well for ordinary wars or revolutions, but some wars and revolutions, being much more extreme than others, are “outliers” in the statistical distribution. Furthermore, notable early wars or revolutions may exert such a strong impact on subsequent events of the same class—we think again of the French Revolution—that caution is necessary in comparing them with their successors, which may be to some extent the product of imitation. Expanding the class of events can be useful, but it is not always appropriate. Another way of dealing scientifically with rare, large-scale events is to engage in counterfactual analysis: “the mental construction of a course of events which is altered through modifications in one or more ‘conditions’” (Weber [1905] 1949:173). The application of this idea in a systematic, scientific way is illustrated in a particularly extreme example of a rare event from geology and evolutionary biology, both historically oriented natural sciences. Stephen J. Gould has suggested that one way to distinguish systematic features of evolution from stochastic, chance events may be to imagine what the world would be like if all conditions up to a specific point were fixed and then the rest of history were rerun. He contends that if it were possible to “replay the tape of life,” to let evolution occur again from the beginning, the world’s organisms today would be a completely different (Gould 1989a). [10.89.91.121] Project MUSE (2025-08-03 03:58 GMT) University of Queensland A unique event on which students of evolution have recently focused is the sudden extinction of the dinosaurs 65 million years ago. Gould (1989a:318) says, “we must assume that consciousness would not have evolved on our planet if a cosmic catastrophe had not claimed the dinosaurs as victims.” If this statement is true, the extinction of the dinosaurs was as important as any historical event for human beings; however, dinosaur extinction does not fall neatly into a class of events that could be studied in a systematic, comparative fashion through the application of general laws in a straightforward way. Nevertheless, dinosaur extinction can be studied scientifically: alternative hypotheses can be developed and tested with respect to their observable implications. One hypothesis to account for dinosaur extinction, developed by Luis Alvarez and collaborators at Berkeley in the late 1970s (W. Alvarez and Asaro, 1990), posits a cosmic collision: a meteorite crashed into the earth at about 72,000 kilometers an hour, creating a blast greater than that from a full-scale nuclear war. If this hypothesis is correct, it would have the observable implication that iridium (an element common in meteorites but rare on earth) should be found in the particular layer of the earth’s crust that corresponds to sediment laid down sixty-five million years ago; indeed, the discovery of iridium at predicted layers in the earth has been taken as partial confirming evidence for the theory. Although this is an unambiguously unique event, there are many other observable implications. For one example, it should be possible to find the meteorite’s crater somewhere on Earth (and several candidates have already been found). However, an alternative hypothesis, that extinction was caused by volcanic eruptions, is also consistent with the presence of iridium, and seems more consistent than the meteorite hypothesis with the finding that all the species extinctions did not occur simultaneously. For our purposes, the point of this example is that scientific generalizations are useful in studying even highly unusual events that do not fall into a large class of events. The Alvarez hypothesis cannot be tested with reference to a set of common events, but it does have observable implications for other phenomena that can be evaluated. We should note, however, that a hypothesis is not considered a reasonably certain explanation until it has been evaluated empirically and passed a number of demanding tests. At a minimum, its implications must be consistent with our knowledge of the external world; at best, it should predict what Imre Lakatos (1970) refers to as “new facts,” that is, those formerly unobserved. The point is that even apparently unique events such as dinosaur extinction can be studied scientifically if we pay attention to improving theory, data, and our use of the data. Improving our theory through conceptual clarification and specification of variables can generate more observable implications and even test causal theories of unique events such as dinosaur extinction. Improving our data allows us to observe more of these observable implications, and improving our use of data permits more of these implications to be extracted from existing data. That a set of events to be studied is highly complex does not render careful research design irrelevant. Whether we study many phenomena or few—or even one—the study will be improved if we collect data on as many observable implications of our theory as possible.

1.2 MAJOR COMPONENTS OF RESEARCH DESIGN

Social science research at its best is a creative process of insight and discovery taking place within a well-established structure of scientific inquiry. The first-rate social scientist does not regard a research design as a blueprint for a mechanical process of data-gathering and evaluation. To the contrary, the scholar must have the flexibility of mind to overturn old ways of looking at the world, to ask new questions, to revise research designs appropriately, and then to collect more data of a different type than originally intended. However, if the researcher’s findings are to be valid and accepted by scholars in this field, all these revisions and reconsiderations must take place according to explicit procedures consistent with the rules of inference. A dynamic process of inquiry occurs within a stable structure of rules. Social scientists often begin research with a considered design, collect some data, and draw conclusions. But this process is rarely a smooth one and is not always best done in this order: conclusions rarely follow easily from a research design and data collected in accordance with it. Once an investigator has collected data as provided by a research design, he or she will often find an imperfect fit among the main research questions, the theory and the data at hand. At this stage, researchers often become discouraged. They mistakenly believe that other social scientists find close, immediate fits between data and research. This perception is due to the fact that investigators often take down the scaffolding after putting up their intellectual buildings, leaving little trace of the agony and uncertainty of construction. Thus the process of inquiry seems more mechanical and cut-and-dried than it actually is. Some of our advice is directed toward researchers who are trying to make connections between theory and data. At times, they can design more appropriate data-collection procedures in order to evaluate a theory better; at other times, they can use the data they have and recast a theoretical question (or even pose an entirely different question that was not originally foreseen) to produce a more important research project. The research, if it adheres to rules of inference, will still be scientific and produce reliable inferences about the world. Wherever possible, researchers should also improve their research designs before conducting any field research. However, data has a way of disciplining thought. It is extremely common to find that the best research design falls apart when the very first observations are collected—it is not that the theory is wrong but that the data are not suited to answering the questions originally posed. Understanding from the outset what can and what cannot be done at this later stage can help the researcher anticipate at least some of the problems when first designing the research. For analytical purposes, we divide all research designs into four components:

  1. The research question

  2. The theory

  3. The data

  4. The use of the data

These components are not necessarily developed in a linear order; for instance, qualitative researchers might start with data. Understanding each component helps researchers make informed compromises given practical constraints, maximizing the quality of their designs.

1.2.1 Improving Research Questions

Throughout this book, we consider what to do once we identify the object of research. Given a research question, what are the ways to conduct that research so that we can obtain valid explanations of social and political phenomena? Our discussion begins with a research question and then proceeds to the stages of designing and conducting the research. But where do research questions originate? How does a scholar choose the topic for analysis? There is no simple answer to this question. Like others, Karl Popper (1968:32) has argued that “there is no such thing as a logical method of having new ideas. . . . Discovery contains ‘an irrational element,’ or a ‘creative intuition.’” The rules of choice at the earliest stages of the research process are less formalized than are the rules for other research activities. There are texts on designing laboratory experiments on social choice, statistical criteria on drawing a sample for a survey of attitudes on public policy, and manuals on conducting participant observation of a bureaucratic office. But there is no rule for choosing which research project to conduct, nor if we should decide to conduct field work, are there rules governing where we should conduct it. We can propose ways to select a sample of communities in order to study the impact of alternative educational policies, or ways to conceptualize ethnic conflict in a manner conducive to the formulation and testing of hypotheses as to its incidence. But there are no rules that tell us whether to study educational policy or ethnic conflict. In terms of social science methods, there are better and worse ways to study the collapse of the East German government in 1989 just as there are better and worse ways to study the relationship between a candidate’s position on taxes and the likelihood of electoral success. But there is no way to determine whether it is better to study the collapse of the East German regime or the role of taxes in U.S. electoral politics. The specific topic that a social scientist studies may have a personal and idiosyncratic origin. It is no accident that research on particular groups is likely to be pioneered by people of that group: women have often led the way in the history of women, blacks in the history of blacks, immigrants in the history of immigration. Topics may also be influenced by personal inclination and values. The student of third world politics is likely to have a greater desire for travel and a greater tolerance for difficult living conditions than the student of congressional policy making; the analyst of international cooperation may have a particular distaste for violent conflict. These personal experiences and values often provide the motivation to become a social scientist and, later, to choose a particular research question. As such, they may constitute the “real” reasons for engaging in a particular research project—and appropriately so. But, no matter how personal or idiosyncratic the reasons for choosing a topic, the methods of science and rules of inference discussed in this book will help scholars devise more powerful research designs. From the perspective of a potential contribution to social science, personal reasons are neither necessary nor sufficient justifications for the choice of a topic. In most cases, they should not appear in our scholarly writings. To put it most directly but quite indelicately, no one cares what we think—the scholarly community only cares what we can demonstrate. Though precise rules for choosing a topic do not exist, there are ways—beyond individual preferences—of determining the likely value of a research enterprise to the scholarly community. Ideally, all research projects in the social sciences should satisfy two criteria.

  1. First, a research project should pose a question that is “important” in the real world. The topic should be consequential for political, social, or economic life, for understanding something that significantly affects many people’s lives, or for understanding and predicting events that might be harmful or beneficial (see Shively 1990:15).

  2. Second, a research project should make a specific contribution to an identifiable scholarly literature by increasing our collective ability to construct verified scientific explanations of some aspect of the world. This latter criterion does not imply that all research that contributes to our stock of social science explanations in fact aims directly at making causal inferences. Sometimes the state of knowledge in a field is such that much fact-finding and description is needed before we can take on the challenge of explanation. Often the contribution of a single project will be descriptive inference. Sometimes the goal may not even be descriptive inference but rather will be the close observation of particular events or the summary of historical detail. These, however, meet our second criterion because they are prerequisites to explanation.

Our first criterion directs our attention to the real world of politics and social phenomena and to the current and historical record of the events and problems that shape people’s lives. Whether a research question meets this criterion is essentially a societal judgment. The second criterion directs our attention to the scholarly literature of social science, to the intellectual puzzles not yet posed, to puzzles that remain to be solved, and to the scientific theories and methods available to solve them. Political scientists have no difficulty finding subject matter that meets our first criterion. Ten major wars during the last four hundred years have killed almost thirty million people (Levy 1985:372); some “limited wars,” such as those between the United States and North Vietnam and between Iran and Iraq, have each claimed over a million lives; and nuclear war, were it to occur, could kill billions of human beings. Political mismanagement, both domestic and international, has led to economic privation on a global basis—as in the 1930s—as well as to regional and local depression, as evidenced by the tragic experiences of much of Africa and Latin America during the 1980s. In general, cross-national variation in political institutions is associated with great variation in the conditions of ordinary human life, which are reflected in differences in life expectancy and infant mortality between countries with similar levels of economic development (Russett 1978:913–28). Within the United States, programs designed to alleviate poverty or social disorganization seem to have varied greatly in their efficacy. It cannot be doubted that research which contributes even marginally to an understanding of these issues is important. While social scientists have an abundance of significant questions that can be investigated, the tools for understanding them are scarce and rather crude. Much has been written about war or social misery that adds little to the understanding of these issues because it fails either to describe these phenomena systematically or to make valid causal or descriptive inferences. Brilliant insights can contribute to understanding by yielding interesting new hypotheses, but brilliance is not a method of empirical research. All hypotheses need to be evaluated empirically before they can make a contribution to knowledge. This book offers no advice on becoming brilliant. What it can do, however, is to emphasize the importance of conducting research so that it constitutes a contribution to knowledge. Our second criterion for choosing a research question, “making a contribution,” means explicitly locating a research design within the framework of the existing social scientific literature. This ensures that the investigator understand the “state of the art” and minimizes the chance of duplicating what has already been done. It also guarantees that the work done will be important to others, thus improving the success of the community of scholars taken as a whole. Making an explicit contribution to the literature can be done in many different ways. We list a few of the possibilities here:

  1. Investigating important hypotheses that lack systematic study.

  2. Examining accepted hypotheses suspected to be false (or one we believe has not been adequately confirmed) and investigate whether it is indeed false or whether some other theory is correct.

  3. Resolving or providing further evidence of one side of a controversy in the literature—perhaps demonstrate that the controversy was unfounded from the start.

  4. Illuminating or evaluating unquestioned assumptions in the literature.

  5. Addressing overlooked important topics with systematic study.

  6. Applying existing theories or evidence designed for some purpose in one literature could be applied in another literature to solve an existing but apparently unrelated problem.

Balancing these two criteria—real-world importance and scholarly contribution—is crucial. Overemphasis on literature can lead to politically insignificant questions, while neglecting scholarly frameworks can result in careless work. The best research strives to bridge both, enhancing real-world understanding through scientific methods and contributing to theoretical advancements. The research design process should always aim to meet both criteria, regardless of the starting point.

1.2.2 Improving Theory

A social science theory is a reasoned and precise speculation about the answer to a research question, including a statement about why the proposed answer is correct. Theories usually imply several more specific descriptive or causal hypotheses. A theory must be consistent with prior evidence about a research question. “A theory that ignores existing evidence is an oxymoron. If we had the equivalent of ‘truth in advertising’ legislation, such an oxymoron should not be called a theory” (Lieberson 1992:4; see also Woods and Walton 1982). The development of a theory is often presented as the first step of research. It sometimes comes first in practice, but it need not. In fact, we cannot develop a theory without knowledge of prior work on the subject and the collection of some data, since even the research question would be unknown. Nevertheless, despite whatever amount of data has already been collected, there are some general ways to evaluate and improve the usefulness of a theory. We briefly introduce each of these here but save a more detailed discussion for later chapters.

  1. First, choose theories that could be wrong. Indeed, vastly more is learned from theories that are wrong than from theories that are stated so broadly that they could not be wrong even in principle. We need to be able to give a direct answer to the question: What evidence would convince us that we are wrong? If there is no answer to this question, then we do not have a theory.

  2. Second, to make sure a theory is falsifiable, choose one that is capable of generating as many observable implications as possible. This choice will allow more tests of the theory with more data and a greater variety of data, will put the theory at risk of being falsified more times, and will make it possible to collect data so as to build strong evidence for the theory.

  3. Third, in designing theories, be as concrete as possible. Vaguely stated theories and hypotheses serve no purpose but to obfuscate. Theories that are stated precisely and make specific predictions can be shown more easily to be wrong and are therefore better.

Some researchers recommend following the principle of “parsimony.” Unfortunately, the word has been used in so many ways in casual conversation and scholarly writings that the principle has become obscured (see Sober [1988] for a complete discussion). The clearest definition of parsimony was given by Jeffreys (1961:47): “Simple theories have higher prior probabilities.” Parsimony is therefore a judgment, or even assumption, about the nature of the world: it is assumed to be simple. The principle of choosing theories that imply a simple world is a rule that clearly applies in situations where there is a high degree of certainty that the world is indeed simple. Scholars in physics seem to find parsimony appropriate, but those in biology often think of it as absurd. In the social sciences, some forcefully defend parsimony in their subfields (e.g., Zellner 1984), but we believe it is only occasionally appropriate. Given the precise definition of parsimony as an assumption about the world, we should never insist on parsimony as a general principle of designing theories, but it is useful in those situations where we have some knowledge of the simplicity of the world we are studying. Our point is that we do not advise researchers to seek parsimony as an essential good, since there seems little reason to adopt it unless we already know a lot about a subject. We do not even need parsimony to avoid excessively complicated theories, since it is directly implied by the maxim that the theory should be just as complicated as all our evidence suggest. Situations with insufficient evidence relative to the complexity of the theory being investigated can lead to what we call “indeterminate research designs” (see section 4.1), but these are problems of research design and not assumptions about the world.

All our advice thus far applies if we have not yet collected our data and begun any analysis. However, if we have already gathered the data, we can certainly use these rules to modify our theory and gather new data, and thus generate new observable implications of the new theory. Of course, this process is expensive, time consuming, and probably wasteful of the data already collected. What then about the situation where our theory is in obvious need of improvement but we cannot afford to collect additional data? This situation—in which researchers often find themselves—demands great caution and self-restraint. Any intelligent scholar can come up with a “plausible” theory for any set of data after the fact, yet to do so demonstrates nothing about the veracity of the theory. The theory will fit the data nicely and still may be wildly wrong—indeed, demonstrably wrong with most other data. Human beings are very good at recognizing patterns but not very good at recognizing nonpatterns. (Most of us even see patterns in random ink blots!) Ad hoc adjustments in a theory that does not fit existing data must be used rarely and with considerable discipline. If we have chosen a topic of real-world importance and/or one which makes some contribution to a scholarly literature, the social nature of academia will correct this situation: someone will replicate our study with another set of data and demonstrate that we were wrong. There is still the problem of what to do when we have finished our data collection and analysis and wish to work on improving a theory. In this situation, we recommend following two rules: First, if our prediction is conditional on several variables and we are willing to drop one of the conditions, we may do so. For example, if we hypothesized originally that democratic countries with advanced social welfare systems do not fight each other, it would be permissible to extend that hypothesis to all modern democracies and thus evaluate our theory against more cases and increase its chances of being falsified. The general point is that after seeing the data, we may modify our theory in a way that makes it apply to a larger range of phenomena. Since such an alteration in our thesis exposes it more fully to falsification, modification in this direction should not lead to ad hoc explanations that merely appear to “save” an inadequate theory by restricting its range to phenomena that have already been observed to be in accord with it. The opposite practice, however, is generally inappropriate. After observing the data, we should not just add a restrictive condition and then proceed as if our theory, with that qualification, has been shown to be correct. If our original theory was that modern democracies do not fight wars with one another due to their constitutional systems, it would be less permissible, having found exceptions to our “rule,” to restrict the proposition to democracies with advanced social welfare systems once it has been ascertained by inspection of the data that such a qualification would appear to make our proposition correct. Or suppose that our original theory was that revolutions only occur under conditions of severe economic depression, but we find that this is not true in one of our case studies. In this situation it would not be reasonable merely to add general conditions such as, revolutions never occur during periods of prosperity except when the military is weak, the political leadership is repressive, the economy is based on a small number of products, and the climate is warm. Such a formulation is merely a fancy (and misleading) way of saying “my theory is correct, except in country x.” Since we have already discovered that our theory is incorrect for country x, it does not help to turn this falsification into a spurious generalization. Without efforts to collect new data, we will have no admissible evidence to support the new version of the theory. So our basic rule with respect to altering our theory after observing the data is: we can make the theory less restrictive (so that it covers a broader range of phenomena and is exposed to more opportunities for falsification), but we should not make it more restrictive without collecting new data to test the new version of the theory. If we cannot collect additional data, then we are stuck; and we do not propose any magical way of getting unstuck. At some point, deciding that we are wrong is best; indeed, negative findings can be quite valuable for a scholarly literature. Who would not prefer one solid negative finding over any number of flimsy positive findings based on ad hoc theories? Moreover, if we are wrong, we need not stop writing after admitting defeat. We may add a section to our article or a chapter to our book about future empirical research and current theoretical speculation. In this context, we have considerably more freedom. We may suggest additional conditions that might be plausibly attached to our theory, if we believe they might solve the problem, propose a modification of another existing theory or propose a range of entirely different theories. In this situation, we cannot conclude anything with a great deal of certainty (except perhaps that the theory we stated at the outset is wrong), but we do have the luxury of inventing new research designs or data-collection projects that could be used to decide whether our speculations are correct. These can be very valuable, especially in suggesting areas where future researchers can look. Admittedly, as we discussed above, social science does not operate strictly according to rules: the need for creativity sometimes mandates that the textbook be discarded! And data can discipline thought. Hence researchers will sometimes, after confronting data, have inspirations about how they should have constructed the theory in the first place. Such a modification, even if restrictive, may be worthwhile if we can convince ourselves and others that modifying the theory in the way that we propose is something we could have done before we collected the data if we had thought of it. But until tested with new data, the status of such a theory will remain very uncertain, and it should be labeled as such. One important consequence of these rules is that pilot projects are often very useful, especially in research where data must be gathered by interviewing or other particularly costly means. Preliminary data gathering may lead us to alter the research questions or modify the theory. Then new data can be gathered to test the new theory, and the problem of using the same data to generate and test a theory can be avoided.

1.2.3 Improving Data Quality

“Data” are systematically collected elements of information about the world. They can be qualitative or quantitative in style. Sometimes data are collected to evaluate a very specific theory, but not so infrequently, scholars collect data before knowing precisely what they are interested in finding out. Moreover, even if data are collected to evaluate a specific hypothesis, researchers may ultimately be interested in questions that had not occurred to them previously. In either case—when data are gathered for a specific purpose or when data are used for some purpose not clearly in mind when they were gathered—certain rules will improve the quality of those data. In principle, we can think about these rules for improving data separately from the rules in section 1.2.2 for improving theory. In practice any data-collection effort requires some degree of theory, just as formulating any theory requires some data (see Coombs 1964). Our first and most important guideline for improving data quality is: record and report the process by which the data are generated. Without this information we cannot determine whether using standard procedures in analyzing the data will produce biased inferences. Only by knowing the process by which the data were generated will we be able to produce valid descriptive or causal inferences. In a quantitative opinion poll, recording the data-generation process requires that we know the exact method by which the sample was drawn and the specific questions that were asked. In a qualitative comparative case study, reporting the precise rules by which we choose the small number of cases for analysis is critical. We give additional guidelines in chapter 6 for case selection in qualitative research, but even more important than choosing a good method is being careful to record and report whatever method was used and all the information necessary for someone else to apply it. We find that many graduate students are unnecessarily afraid of sharing data and the information necessary to replicate their results. They are afraid that someone will steal their hard work or even prove that they were wrong. These are all common fears, but they are almost always unwarranted. Publication (or at least sending copies of research papers to other scholars) and sharing data is the best way to guarantee credit for one’s contributions. Moreover, sharing data will only help others follow along in the research you started. When their research is published, they will cite your effort and advance your visibility and reputation. In section 1.2.2 we argued for theories that are capable of generating many observable implications. Our second guideline for improving data quality is in order better to evaluate a theory, collect data on as many of its observable implications as possible. This means collecting as much data in as many diverse contexts as possible. Each additional implication of our theory which we observe provides another context in which to evaluate its veracity. The more observable implications which are found to be consistent with the theory, the more powerful the explanation and the more certain the results. When adding data on new observable implications of a theory, we can (a) collect more observations on the same dependent variable, or (b) record additional dependent variables. We can, for instance, disaggregate to shorter time periods or smaller geographic areas. We can also collect information on dependent variables of less direct interest; if the results are as the theory predicts, we will have more confidence in the theory. For example, consider the rational deterrence theory: potential initiators of warfare calculate the costs and benefits of attacking other states, and these calculations can be influenced by credible threats of retaliation. The most direct test of this theory would be to assess whether, given threats of war, decisions to attack are associated with such factors as the balance of military forces between the potential attacker and the defender or the interests at stake for the defender (Huth 1988). However, even though using only cases in which threats are issued constitutes a set of observable implications of the theory, they are only part of the observations that could be gathered (and used alone may lead to selection bias), since situations in which threats themselves are deterred would be excluded from the data set. Hence it might be worthwhile also to collect data on an additional dependent variable (i.e., a different set of observable implications) based on a measurement of whether threats are made by states that have some incentives to do so. Insofar as sufficient good data on deterrence in international politics is lacking, it could also be helpful to test a different theory, one with similar motivational assumptions, for a different dependent variable under different conditions but which is still an observable implication of the same theory. For instance, we could construct a laboratory experiment to see whether, under simulated conditions, “threats” are deterred rather than accentuated by military power and firm bargaining behavior. Or we could examine whether other actors in analogous situations, such as oligopolistic firms competing for market share or organized-crime families competing for turf, use deterrence strategies and how successful they are under varying conditions. Indeed, economists working in the field of industrial organization have used non-cooperative game theory, on which deterrence theory also relies, to study such problems as entry into markets and pricing strategies (Fudenberg and Tirole 1989). Given the close similarity between the theories, empirical evidence supporting game theory’s predictions about firm behavior would increase the plausibility of related hypotheses about state behavior in international politics. Uncertainty would remain about the applicability of conclusions from one domain to another, but the issue is important enough to warrant attempts to gain insight and evidence wherever they can be found. Obviously, to collect data forever without doing any analysis would preclude rather than facilitate completion of useful research. In practice, limited time and resources will always constrain data-collection efforts. Although more information, additional cases, extra interviews, another variable, and other relevant forms of data collection will always improve the certainty of our inferences to some degree, promising, potential scholars can be ruined by too much information as easily as by too little. Insisting on reading yet another book or getting still one more data set without ever writing a word is a prescription for being unproductive. Our third guideline is: maximize the validity of our measurements. Validity refers to measuring what we think we are measuring. The unemployment rate may be a good indicator of the state of the economy, but the two are not synonymous. In general, it is easiest to maximize validity by adhering to the data and not allowing unobserved or unmeasurable concepts get in the way. If an informant responds to our question by indicating ignorance, then we know he said that he was ignorant. Of that, we have a valid measurement. However, what he really meant is an altogether different concept—one that cannot be measured with a high degree of confidence. For example, in countries with repressive governments, expressing ignorance may be a way of making a critical political statement for some people; for others, it is a way of saying “I don’t know.” Our fourth guideline is: ensure that data-collection methods are reliable. Reliability means that applying the same procedure in the same way will always produce the same measure. When a reliable procedure is applied at different times and nothing has happened in the meantime to change the “true” state of the object we are measuring, the same result will be observed. We can check reliability ourselves by measuring the same quantity twice and seeing whether the measures are the same. Sometimes this seems easy, such as literally asking the same question at different times during an interview. However, asking the question once may influence the respondent to respond in a consistent fashion the second time, so we need to be careful that the two measurements are indeed independent. Reliable measures also produce the same results when applied by different researchers, and this outcome depends, of course, upon there being explicit procedures that can be followed. An example is the use of more than one coder to extract systematic information from transcripts of in-depth interviews. If two people use the same coding rules, we can see how often they produce the same judgment. If they do not produce reliable measures, then we can make the coding rules more precise and try again. Eventually, a set of rules can often be generated so that the application of the same procedure by different coders will yield the same result. Our final guideline is: all data and analyses should, insofar as possible, be replicable. Replicability applies not only to data, so that we can see whether our measures are reliable, but to the entire reasoning process used in producing conclusions. On the basis of our research report, a new researcher should be able to duplicate our data and trace the logic by which we reached our conclusions. Replicability is important even if no one actually replicates our study. Only by reporting the study in sufficient detail so that it can be replicated is it possible to evaluate the procedures followed and methods used. Replicability of data may be difficult or impossible in some kinds of research: interviewees may die or disappear, and direct observations of real-world events by witnesses or participants cannot be repeated. Replicability has also come to mean different things in different research traditions. In quantitative research, scholars focus on replicating the analysis after starting with the same data. As anyone who has ever tried to replicate the quantitative results of even prominent published works knows well, it is usually a lot harder than it should be and always more valuable than it seems at the outset (see Dewald et al. 1986 on replication in quantitative research). The analogy in traditional qualitative research is provided by footnotes and bibliographic essays. Using these tools, succeeding scholars should be able to locate the sources used in published work and make their own evaluations of the inferences claimed from this information. For research based on direct observation, replication is more difficult. One scholar could borrow another’s field notes or tape recorded interviews to see whether they support the conclusions made by the original investigator. Since so much of the data in field research involve conversations, impressions, and other unrecorded participatory information, this reanalysis of results using the same data is not often done. However, some important advances might be achieved if more scholars tried this type of replication, and it would probably also encourage others to keep more complete field notes. Occasionally, an entire research project, including data collection, has been replicated. Since we cannot go back in time, the replication cannot be perfect but can be quite valuable nonetheless. Perhaps the most extensive replication of a qualitative study is the sociological study of Middletown, Indiana, begun by Robert and Helen Lynd. Their first “Middletown” study was published in 1929 and was replicated in a book published in 1937. Over fifty years after the original study, a long series of books and articles are being published that replicate these original studies (see Caplow et al., 1983a, 1983b and the citations therein). All qualitative replication need not be this extensive, but this major research project should serve as an exemplar for what is possible. All research should attempt to achieve as much replicability as possible: scholars should always record the exact methods, rules, and procedures used to gather information and draw inferences so that another researcher can do the same thing and draw (one hopes) the same conclusion. Replicability also means that scholars who use unpublished or private records should endeavor to ensure that future scholars will have access to the material on similar terms; taking advantage of privileged access without seeking access for others precludes replication and calls into question the scientific quality of the work. Usually our work will not be replicated, but we have the responsibility to act as if someone may wish to do so. Even if the work is not replicated, providing the materials for such replication will enable readers to understand and evaluate what we have done.

1.2.4 Improving the Use of Existing Data

While collecting new and better data is preferable, social scientists often have to make the best of existing, flawed data. Improving the use of previously collected data is the main topic taught in classes on statistical methods and is, indeed, the chief contribution of inferential statistics to the social sciences. The precepts on this topic that are so clear in the study of inferential statistics also apply to qualitative research. The remainder of this book deals with these precepts more fully. Here we provide merely a brief outline of the guidelines for improving the use of previously collected data.

  1. First, whenever possible, we should use data to generate inferences that are “unbiased,” that is, correct on average. To understand this very specific idea from statistical research, imagine applying the same methodology (in quantitative or qualitative research) for analyzing and drawing conclusions from data across many data sets. Because of small errors in the data or in the application of the procedure, a single application of this methodology would probably never be exactly correct. An “unbiased” procedure will be correct when taken as an average across many applications—even if no single application is correct. The procedure will not systematically tilt the outcome in one direction or another. Achieving unbiased inferences depends, of course, both on the original collection of the data and its later use; and, as we pointed out before, it is always best to anticipate problems before data collection begins. However, we mention these issues briefly here because when using the data, we need to be particularly careful to analyze whether sources of bias were overlooked during data collection. One such source, which can lead to biased inferences, is that of selection bias: choosing observations in a manner that systematically distorts the population from which they were drawn. Although an obvious example is deliberately choosing only cases which support our theory, selection bias can occur in much more subtle ways. Another difficulty can result from omitted variable bias, which refers to the exclusion of some control variable that might influence a seeming causal connection between our explanatory variables and that which we want to explain. We discuss these and numerous other potential pitfalls in producing unbiased inferences in chapters 2–6.

  2. The second guideline is based on the statistical concept of “efficiency”: an efficient use of data involves maximizing the information used for descriptive or causal inference. Maximizing efficiency requires not only using all our data, but also using all the relevant information in the data to improve inferences. For example, if the data are disaggregated into small geographical units, we should use it that way, not just as a national aggregate. The smaller aggregates will have larger degrees of uncertainty associated with them, but if they are, at least in part, observable implications of the theory, they will contain some information which can be brought to bear on the inference problem.

1.3 THEMES OF THIS VOLUME

This section highlights four important themes in developing research designs.

1.3.1 Using Observable Implications to Connect Theory and Data

Every worthwhile theory must have implications about the observations we expect to find if the theory is correct. These observable implications of the theory must guide our data collection, and help distinguish relevant from irrelevant facts. In chapter 2.6 we discuss how theory affects data collection, as well as how data disciplines theoretical imagination. Here, we want to stress that theory and empirical research must be tightly connected. Any theory that does real work for us has implications for empirical investigation; no empirical investigation can be successful without theory to guide its choice of questions. Theory and data collection are both essential aspects of the process by which we seek to decide whether a theory should be provisionally viewed true or false, subject as it is in both cases to the uncertainty that characterizes all inference. We should ask of any theory: What are its observable implications? We should ask about any empirical investigations: Are the observations relevant to the implications of our theory, and, if so, what do they enable us to infer about the correctness of the theory? In any social scientific study, the implications of the theory and the observation of facts need to mesh with one another: social science conclusions cannot be considered reliable if they are not based on theory and data in strong connection with one another and forged by formulating and examining the observable implications of a theory.

1.3.2 Maximizing Leverage

The scholar who searches for additional implications of a hypothesis is pursuing one of the most important achievements of all social science: explaining as much as possible with as little as possible. Good social science seeks to increase the significance of what is explained relative to the information used in the explanation. If we can accurately explain what at first appears to be a complicated effect with a single causal variable or a few variables, the leverage we have over a problem is very high. Conversely, if we can explain many effects on the basis of one or a few variables we also have high leverage. Leverage is low in the social sciences in general and even more so in particular subject areas. This may be because scholars do not yet know how to increase it or because nature happens not to be organized in a convenient fashion or for both of these reasons. Areas conventionally studied qualitatively are often those in which leverage is low. Explanation of anything seems to require a host of explanatory variables: we use a lot to explain a little. In such cases, our goal should be to design research with more leverage. There are various ways in which we can increase our leverage over a research problem. The primary way is to increase the number of observable implications of our hypothesis and seek confirmation of those implications. As we have described above, this task can involve

  1. improving the theory so that it has more observable implications,

  2. improving the data so more of these implications are indeed observed and used to evaluate the theory, and

  3. improving the use of the data so that more of these implications are extracted from existing data.

This is distinct from parsimony, which is an assumption about the world’s simplicity. Researchers should routinely list all possible observable implications of their hypothesis that might be observed in their data or in other data. It may be possible to test some of these new implications in the original data set—as long as the implication does not “come out of” the data but is a hypothesis independently suggested by the theory or a different data set. But it is better still to turn to other data. Thus we should also consider implications that might appear in other data—such as data about other units, data about other aspects of the units under study, data from different levels of aggregation, and data from other time periods such as predictions about the near future—and evaluate the hypothesis in those settings. The more evidence we can find in varied contexts, the more powerful our explanation becomes, and the more confidence we and others should have in our conclusions. At first thought, some researchers may object to the idea of collecting observable implications from any source or at any level of aggregation different from that for which the theory was designed. For example, Lieberson (1985) applies to qualitative research the statistical idea of “ecological fallacy”—incorrectly using aggregate data to make inferences about individuals—to warn against cross-level inference. The phrase “ecological fallacy” is confusing because the process of reasoning from aggregate- to individual-level processes is neither ecological nor a fallacy. “Ecological” is an unfortunate choice of word to describe the aggregate level of analysis. Although Robinson (1990) concluded in his original article about this topic that using aggregate analysis to reason about individuals is a fallacy, quantitative social scientists and statisticians now widely recognize that some information about individuals does exist at aggregate levels of analysis, and many methods of unbiased “ecological” inference have been developed. We certainly agree that we can use aggregate data to make incorrect inferences about individuals: if we are interested in individuals, then studying individuals is generally a better strategy if we can obtain these data. However, if the inference we seek to make is more than a very narrowly cast hypothesis, our theory may have implications at many levels of analysis, and we will often be able to use data from all these levels to provide some information about our theory. Thus, even if we are primarily interested in an aggregate level of analysis, we can often gain leverage about our theory’s veracity by looking at the data from these other levels. For example, if we develop a theory to explain revolutions, we should look for observable implications of that theory not only in overall outcomes but also such phenomena as the responses to in-depth interviews of revolutionaries, the reactions of people in small communities in minor parts of the country, and official statements by party leaders. We should be willing to take whatever information we can acquire so long as it helps us learn about the veracity of our theory. If we can test our theory by examining outcomes of revolutions, fine. But in most cases very little information exists at that level, perhaps just one or a few observations, and their values are rarely unambiguous or measured without error. Many different theories are consistent with the existence of a revolution. Only by delving deeper in the present case, or bringing in relevant information existing in other cases, is it possible to distinguish among previously indistinguishable theories. The only issue in using information at other levels and from other sources to study a theory designed at an aggregate level is whether these new observations contain some information that is relevant to evaluating implications of our theory. If these new observations help to test our theory, they should be used even if they are not the implications of greatest interest. For example, we may not care at all about the views of revolutionaries, but if their answers to our questions are consistent with our theory of revolutions, then the theory itself will be more likely to be correct, and the collection of additional information will have been useful. In fact, an observation at the most aggregate level of data analysis—the occurrence of a predicted revolution, for example—is merely one observed implication of the theory, and because of the small amount of information in it, it should not be privileged over other observable implications. We need to collect information on as many observable implications of our theory as possible.

1.3.3 Reporting Uncertainty

All knowledge and all inference—in quantitative and in qualitative research—is uncertain. Qualitative measurement is error-prone, as is quantitative, but the sources of error may differ. The qualitative interviewer conducting a long, in-depth interview with a respondent whose background he has studied is less likely to mismeasure the subject’s real political ideology than is a survey researcher conducting a structured interview with a randomly selected respondent about whom he knows nothing. (Although the opposite is also possible if, for instance, he relies too heavily on an informant who is not trustworthy.) However, the survey researcher is less likely to generalize inappropriately from the particular cases interviewed to the broader population than is the in-depth researcher. Neither is immune from the uncertainties of measurement or the underlying probabilistic nature of the social world. All good social scientists—whether in the quantitative or qualitative traditions—report estimates of the uncertainty of their inferences. Perhaps the single most serious problem with qualitative research in political science is the pervasive failure to provide reasonable estimates of the uncertainty of the investigator’s inferences (see King 1990). We can make a valid inference in almost any situation, no matter how limited the evidence, by following the rules in this book, but we should avoid forging sweeping conclusions from weak data. The point is not that reliable inferences are impossible in qualitative research, but rather that we should always report a reasonable estimate of the degree of certainty we have in each of our inferences. Neustadt and May (1986:274), dealing with areas in which precise quantitative estimates are difficult, propose a useful method of encouraging policymakers (who are often faced with the necessity of reaching conclusions about what policy to follow out of inadequate data) to judge the uncertainty of their conclusions. They ask “How much of your own money would you wager on it?” This makes sense as long as we also ask, “At what odds?”

1.3.4 Thinking like a Social Scientist: Skepticism and Rival Hypotheses

The uncertainty of causal inferences means that good social scientists do not easily accept them. When told A causes B, someone who “thinks like a social scientist” asks whether that connection is a true causal one. It is easy to ask such questions about the research of others, but it is more important to ask them about our own research. There are many reasons why we might be skeptical of a causal account, plausible though it may sound at first glance. We read in the newspaper that the Japanese eat less red meat and have fewer heart attacks than Americans. This observation alone is interesting. In addition, the explanation—too much steak leads to the high rate of heart disease in the United States—is plausible. The skeptical social scientist asks about the accuracy of the data (how do we know about eating habits? what sample was used? are heart attacks classified similarly in Japan and the United States so that we are comparing similar phenomena?). Assuming that the data are accurate, what else might explain the effects: Are there other variables (other dietary differences, genetic features, lifestyle characteristics) that might explain the result? Might we have inadvertently reversed cause and effect? It is hard to imagine how not having a heart attack might cause one to eat less red meat but it is possible. Perhaps people lose their appetite for hamburgers and steak late in life. If this were the case, those who did not have a heart attack (for whatever reason) would live longer and eat less meat. This fact would produce the same relationship that led the researchers to conclude that meat was the culprit in heart attacks. It is not our purpose to call such medical studies into question. Rather we wish merely to illustrate how social scientists approach the issue of causal inference: with skepticism and a concern for alternative explanations that may have been overlooked. Causal inference thus becomes a process whereby each conclusion becomes the occasion for further research to refine and test it. Through successive approximations we try to come closer and closer to accurate causal inference.

1 The Science in Social Science

1.1 Introduction

This book is all about how to do research in social sciences so you can figure out reliable answers about how people and groups behave. Even though it talks a lot about political science, the ideas are useful for many fields like sociology (studying society), anthropology (studying human cultures), economics (studying money and resources), psychology (studying the mind), and even things like legal issues or education research. The main goal is very practical: to show you how to ask good research questions and design your studies so you can get trustworthy conclusions about why things happen (descriptive inference) or what causes what (causal inference). It focuses on the basic way of thinking that all social science research shares.

1.1.1 Two Styles of Research, One Logic of Inference

Even though people talk about "quantitative" (using numbers) and "qualitative" (using descriptions) research as very different, they actually use the same fundamental way of thinking to figure things out. Their differences are mostly about style or how they get specific information. Quantitative research uses numbers, math, and statistics. It tries to measure things precisely with numbers, look for general patterns or causes, and make sure others can repeat its steps easily. Qualitative research, on the other hand, doesn't use numbers. It often looks at a small number of specific situations, uses in-depth interviews or detailed historical studies, explains things in words, and tries to give a full picture of an event or group. Both types can gather a huge amount of information.

Historically, there have been big arguments in social sciences between studying individual cases versus using statistics, or between "scientific" (quantitative) methods and "historical" (qualitative) ways. But this book argues these differences are not that deep. All strong research comes from the same basic rules of figuring things out, which means both quantitative and qualitative methods can be structured and scientific. The best research often combines parts of both, like studies that mix number analysis with detailed case stories.

The rules for doing scientific research explained here apply to any study that wants to find out facts about the real world. This is what makes social science different from just casual observations. This approach assumes we can only know some things about the world, and even then, our understanding won't be perfect. However, by carefully following these rules, we can make our conclusions more reliable, accurate, and honest. The aim is to help you think in a disciplined way, not to force strict rules, because real research always involves applying ideal standards to studies and information that are never perfect.

1.1.2 Defining Scientific Research in the Social Sciences

"Scientific research," as described here, is an ideal standard that all actual studies, whether quantitative or qualitative, try to reach. No matter the style, scientific research design always has four main characteristics:

  1. The goal is to discover something new (inference): Scientific research aims to learn things (descriptive or explanatory inferences) from observed facts. It's not enough to just collect facts; scientific research means going beyond those facts to understand something broader that isn't directly seen. This includes:

    • Descriptive inference: Learning about unknown facts from the facts you've observed.

    • Causal inference: Learning about cause-and-effect relationships from the data.
      The idea is always to draw conclusions that go beyond just the specific things you looked at.

  2. The steps are public: Scientific research uses clear, organized, and openly shared methods for collecting and analyzing data. This transparency means anyone can check how reliable the research is. Because the methods are public, other scholars can judge the work, learn from it, and even try to repeat it. This is different from research where the methods are kept secret or vague.

  3. The conclusions are not 100% certain: Discovering new knowledge is never perfect. It's impossible to get perfectly certain answers from information that isn't perfectly certain. Recognizing and reporting how uncertain your conclusions are is a key part of all scientific knowledge. Without knowing how sure (or unsure) you are, any descriptions or causal explanations about the real world can't be properly understood.

  4. The method is the core (content is the method): The true meaning of "science" lies in its methods and rules for drawing conclusions, not in what it studies. These methods can be used to study almost anything. As one famous scholar said, "the unity of all science consists alone in its method, not in its material." (This means science is defined by how you discover things, not what you discover).

These four points also mean that science works best as a team effort (social enterprise). Every researcher has limitations and will make mistakes, but because scientific work is public and shared, others in the community are likely to find and correct those errors. Research is a valuable contribution when it deals with concerns of other scholars and uses public, consistent methods to draw conclusions.

1.1.3 Science and Complexity

Social science tries to understand social situations that often seem very complicated. However, how "complex" something seems actually depends on how well we can simplify it by clearly defining what we're looking at and what we think explains it. This simplification ability is related to how good our existing theories are. Scientific methods are useful for both simple and complex events. While complexity might make our conclusions less certain, it doesn't make the study less scientific. In fact, the rules of scientific reasoning are most helpful precisely when you have limited information, imperfect tools, and unclear relationships.

Even seemingly unique and complex events, like the fall of the Roman Empire or the extinction of dinosaurs, can be studied scientifically. One way is to look for general rules by thinking of these unique events as examples of a broader category. Another way is to do counterfactual analysis—which means imagining what would have happened if certain conditions were changed. For example, the theory about dinosaurs dying out because of a meteorite collision (the Alvarez hypothesis) suggests observable things we should find, like a rare element called iridium in geological layers from that time. This allows us to test a hypothesis even for a unique event.

Ultimately, scientific generalizations are useful for unusual events if they lead to observable implications—things we can actually look for and check. A hypothesis isn't considered definitely correct until it has passed many difficult real-world tests and, ideally, predicts things we hadn't observed before ("new facts"). Research design, especially in making theories, collecting data, and using data better, is extremely important even for very complex things. The more observable implications of a theory you collect data on, the better your study will be.

1.2 MAJOR COMPONENTS OF RESEARCH DESIGN

Good social science research is a creative process that happens within a structured scientific framework. A good social scientist understands that research design is not just a rigid plan; they need to be flexible enough to change their views, ask new questions, adjust their designs, and even collect different types of data if needed. However, for the findings to be valid and accepted, all these changes must follow explicit procedures that align with the rules of scientific reasoning. It's an ongoing process where the original plans often don't perfectly match the data, leading to adjustments in questions or theories.

Research design can be broken down into four main parts:

  1. The research question (what you want to find out)

  2. The theory (your educated guess about why)

  3. The data (the information you collect)

  4. How you use the data (how you analyze and interpret it)

These parts don't necessarily happen in a strict order; for example, qualitative researchers might start by collecting data. Understanding each component helps researchers make smart choices when faced with practical limits, making their studies as good as possible.

1.2.1 Improving Research Questions

Choosing a research topic often involves personal interests and a bit of a "creative intuition," as philosopher Karl Popper suggested. There aren't strict rules for picking a topic, unlike rules for designing surveys or conducting fieldwork. While personal reasons for choosing a topic are fine, to make a real contribution to social science, the research methods and rules of scientific reasoning are what truly improve the study. From an academic viewpoint, personal reasons alone aren't enough to justify a topic.

Ideally, all social science research projects should meet two main conditions to be most valuable to the academic community:

  1. Be "important" in the real world: The question should matter for political, social, or economic life, significantly affecting many people or helping us understand and predict useful or harmful events. This judgment primarily comes from society.

  2. Make a specific contribution to existing academic work: The project should help us collectively build better scientific explanations. This could involve describing things accurately, making critical observations, or summarizing history, which are all necessary steps before explaining causes.

Social scientists have plenty of important real-world issues to study (like wars or poverty), but good tools for understanding them are rare. Brilliant ideas alone aren't enough; every idea (hypothesis) needs to be tested with evidence to add to our knowledge. Making an academic contribution means clearly placing your research within what others have already studied, so you understand the current knowledge, avoid repeating work, and ensure your work is relevant to other scholars. Contributions can come in many forms:

  1. Studying important ideas that haven't been systematically investigated yet.

  2. Checking if widely accepted ideas are actually false or haven't been well-proven.

  3. Helping to resolve debates in academic literature or adding more evidence to one side.

  4. Examining or questioning assumptions that are usually taken for granted.

  5. Systematically studying important topics that have been ignored.

  6. Applying existing theories or evidence from one area of study to solve a problem in another, seemingly unrelated area.

Balancing these two criteria—real-world importance and academic contribution—is vital. Focusing too much on academic literature can lead to questions that aren't very useful in the real world, while ignoring academic frameworks can lead to sloppy work. The best research bridges both, improving our understanding of the real world using scientific methods and advancing academic theories. The research design process should always aim for both, no matter where you start.

1.2.2 Improving Theory

A social science theory is a careful and precise guess about the answer to your research question. It explains why the answer might be correct and leads to more specific ideas (hypotheses) that can be tested. A good theory must also fit with what we already know from previous evidence. As one scholar put it, "A theory that ignores existing evidence is an oxymoron" (meaning it's a contradiction in terms).

To make your theory better, especially before you collect and analyze your data, here are some important guidelines:

  1. It must be testable (falsifiable): Your theory should be able to be proven wrong by evidence. If you can't imagine any evidence that would show your theory is incorrect, then it's not a true scientific theory. You need to be able to answer: "What information would show me that I'm wrong?"

  2. Generate many observable implications: Design your theory so it leads to as many different things you can actually observe as possible. This allows for more ways to test your theory using various types of data. The more tests it goes through and survives, the stronger the evidence supporting it.

  3. Be specific and clear (concreteness): State your theories and hypotheses precisely. Vague statements only make things confusing. Theories that are specific and make clear predictions are easier to disprove, and therefore, they are better scientific theories.

The idea of parsimony (that simpler theories are more likely to be true) is sometimes discussed. This concept assumes that the world is simple. It might be good in fields like physics, but not always in social sciences. We should only use parsimony if we already have good reason to believe the part of the world we're studying is simple. Otherwise, theories should be as complex as the evidence suggests.

If you've already collected data, improving your theory needs to be done carefully. Making quick changes (ad hoc adjustments) to your theory just to make it fit your existing data can be misleading. Generally, it's okay to make a theory less restrictive (meaning it applies to more situations) after looking at your data, because this gives it more chances to be proven wrong. However, it's usually wrong to make your theory more restrictive (narrowing its scope to fit exceptions you found) unless you collect brand new data to test this modified version. Such changes just make it seem like your theory is correct when it was actually proven wrong, without any new real support.

If you can't collect new data, sometimes the best thing to do is admit your original theory was wrong; negative findings can be very useful. You can then suggest other ideas or theories for future research, but you must be clear about how uncertain these suggestions are. Pilot projects (small, preliminary studies) are very helpful. They allow you to collect some initial data, adjust your theory or questions based on what you find, and then collect new data to test the refined theory, avoiding the problem of using the same data for both developing and testing your ideas.

1.2.3 Improving Data Quality

"Data" means any systematically gathered information about the world, whether it's numbers or descriptions. No matter if you collect data for a specific idea or just to explore, certain guidelines help make it better:

  1. Always describe how you got your data: This is the most important rule. If you don't explain exactly how your data was collected (e.g., how you picked people for a survey, what questions you asked, or how you chose specific cases), no one can know if your conclusions are reliable. Being transparent helps ensure your findings are trustworthy.

  2. Collect data on many "observable implications" of your theory: To thoroughly test your theory, gather information on as many different things that your theory predicts as possible, and from various situations. Every piece of information that aligns with your theory makes it stronger. This means:

    • Collecting more observations on the same outcome (e.g., looking at shorter time periods or smaller geographic areas).

    • Collecting information on additional outcomes (dependent variables) that your theory might also predict (e.g., if your theory is about deterring attacks, also look at whether threats themselves are deterred).

    • Comparing your theory in similar situations (e.g., how deterrence works in international politics versus how it works among competing businesses) can also give insights, even if not directly applicable.

  3. Make sure your measurements are valid: "Validity" means you are truly measuring what you intend to measure. It's best to stick closely to what you can actually observe and avoid relying on concepts that are hard to see or measure directly. For example, if someone says "I don't know" in an interview, you've validly measured that they said "I don't know." What they really meant by that (e.g., ignorance vs. a subtle protest) is a harder, less valid measurement.

  4. Ensure your data-collection methods are reliable: "Reliability" means that if you use the same method in the same way, you should get the same result every time, assuming the thing you're measuring hasn't changed. Explicit procedures help different researchers get the same results, making their work comparable (e.g., having multiple people interpret qualitative data using the same rules).

  5. All data and analyses should be replicable: Your research should be described in enough detail that another researcher could gather the same data and follow your reasoning to reach your conclusions. Replicability is crucial for checking your methods, even if no one actually repeats your study. For number-based research, this often means providing your dataset so others can re-do your analysis. For qualitative research, it means providing detailed source information (like footnotes) and, if possible, allowing access to your raw notes or interviews. While perfect replication might be tough (e.g., for historical events), the commitment to transparency makes research more scientific. Large-scale projects, like the decades-long replication of the "Middletown" studies, show what's possible.

1.2.4 Improving the Use of Existing Data

While getting new and better data is usually best for solving data problems, it's not always possible. Social scientists often have to work with existing data that might have flaws. Learning how to better use data that's already been collected is a big part of statistical methods and is a key contribution of using statistics in social science. The clear rules from statistical studies also apply to qualitative research. Here are some brief guidelines for using existing data better:

  1. Aim for "unbiased" conclusions: You want your conclusions to be correct on average if you were to apply your methods many times. Even if each individual study might not be perfectly accurate due to small errors, an "unbiased" method won't systematically lean the results in one wrong direction. Achieving unbiased conclusions depends on both how data was originally collected and how it's used later. It's always best to foresee problems before collecting data. When using existing data, you need to be very careful to check for biases that might have been missed during original collection. Two common biases are:

    • Selection bias: This happens when observations (cases) are chosen in a way that unfairly represents the group they came from. For instance, only picking cases that support your theory is a clear example, but it can be more subtle.

    • Omitted variable bias: This occurs when you leave out an important factor (control variable) that influences both what you're trying to explain and your supposed cause, making it seem like there's a connection when there might not be.

  2. Maximize efficiency: This means using all your data and all the relevant information within it to get the most out of it for drawing conclusions. For example, if data is available for small geographical areas, you should use it at that detailed level, not just as a big national total. Even if the smaller details have more uncertainty, they still contain valuable information that can help you understand your theory.

1.3 THEMES OF THIS VOLUME

This section highlights four important running themes in developing research designs:

1.3.1 Using Observable Implications to Connect Theory and Data

Every good theory must have predictions about what you should see if the theory is correct. These observable implications (what you expect to observe) of your theory should guide how you collect data and help you tell what facts are important versus irrelevant. Theory and actual research must be closely linked: research without a guiding theory won't succeed, and a theory without observable predictions is useless. For any theory, you should ask: "What would I expect to see if this theory were true?" And for any observations, you should ask: "Are these observations relevant to my theory's predictions, and what do they tell me about whether my theory is correct?" In social science, your theory's predictions and your observations must fit together. Social science conclusions aren't reliable unless they're built on a strong connection between theory and data, created by carefully thinking about and checking the theory's observable implications.

1.3.2 Maximizing Leverage

Maximizing leverage in social science means trying to explain as much as possible using as little information as possible. You have high leverage when you can explain a complex outcome with just one or a few variables, or when you can explain many different outcomes with just one or a few variables. In general, social sciences, especially qualitative studies, often have low leverage, meaning you need many variables to explain only a little. The goal of research should be to increase this leverage. You can do this by:

  1. Making your theory better so it predicts more observable things.

  2. Improving your data collection so you can actually observe and use more of those predictions.

  3. Improving how you use your existing data to extract more predictions from it.

This idea is different from "parsimony" (which is an assumption that the world itself is simple). Researchers should regularly list all possible things their theory predicts that could be observed in their data or in other data. It's often better to test these new predictions with new or different data, such as data from other types of groups, other aspects of the same groups, different levels of detail (like local vs. national), or different time periods. The more evidence you find that supports your theory across various situations, the stronger your explanation becomes, and the more confidence everyone should have in your conclusions. Even data from different levels of analysis can provide useful information for evaluating a theory, because all observable implications add to its truthfulness.

1.3.3 Reporting Uncertainty

All knowledge and conclusions—in both quantitative and qualitative research—are always uncertain. Both ways of measuring things can have errors, even if those errors come from different sources. A major problem in qualitative research is that often researchers don't provide good estimates of how uncertain their conclusions are. You can make valid conclusions even with limited information by following these rules, but you shouldn't make big, sweeping claims based on weak data. The point isn't that reliable conclusions are impossible in qualitative research, but that you must always report a reasonable estimate of how sure you are about each of your conclusions. One way to think about uncertainty, especially when precise numbers are hard to get, is to ask yourself: "How much of your own money would you bet on this conclusion, and what odds would you expect?"

1.3.4 Thinking like a Social Scientist: Skepticism and Rival Hypotheses

Because causal conclusions are uncertain, good social scientists don't just accept them easily. When someone claims "A causes B," a social scientist will immediately question whether that connection is truly a cause-and-effect relationship. It's easy to question others' research, but it's even more important to question your own. There are many reasons to be skeptical of a causal story, even if it sounds good at first glance. For example, if a newspaper says Japanese people eat less red meat and have fewer heart attacks than Americans, and suggests eating too much steak causes heart disease, a skeptical social scientist would ask:

  • How accurate is the data? (How do they know about eating habits? What group was studied? Are heart attack definitions the same in both countries?)

  • What else could explain this? (Are there other diet differences, genetic factors, or lifestyle choices that might be responsible?)

  • Could the causation be reversed? (Could not having a heart attack make people eat less red meat later in life?)

The goal isn't to disprove medical studies but to show how social scientists approach causal claims: with skepticism and a constant

1 The Science in Social Science

1.1 Introduction

This book is all about how to do research in social sciences so you can figure out reliable answers about how people and groups behave. Even though it talks a lot about political science, the ideas are useful for many fields like sociology (studying society), anthropology (studying human cultures), economics (studying money and resources), psychology (studying the mind), and even things like legal issues or education research. The main goal is very practical: to show you how to ask good research questions and design your studies so you can get trustworthy conclusions about why things happen (descriptive inference) or what causes what (causal inference). It focuses on the basic way of thinking that all social science research shares.

1.1.1 Two Styles of Research, One Logic of Inference

Even though people talk about "quantitative" (using numbers) and "qualitative" (using descriptions) research as very different, they actually use the same fundamental way of thinking to figure things out. Their differences are mostly about style or how they get specific information. Quantitative research uses numbers, math, and statistics. It tries to measure things precisely with numbers, look for general patterns or causes, and make sure others can repeat its steps easily. Qualitative research, on the other hand, doesn't use numbers. It often looks at a small number of specific situations, uses in-depth interviews or detailed historical studies, explains things in words, and tries to give a full picture of an event or group. Both types can gather a huge amount of information.

Historically, there have been big arguments in social sciences between studying individual cases versus using statistics, or between "scientific" (quantitative) methods and "historical" (qualitative) ways. But this book argues these differences are not that deep. All strong research comes from the same basic rules of figuring things out, which means both quantitative and qualitative methods can be structured and scientific. The best research often combines parts of both, like studies that mix number analysis with detailed case stories.

The rules for doing scientific research explained here apply to any study that wants to find out facts about the real world. This is what makes social science different from just casual observations. This approach assumes we can only know some things about the world, and even then, our understanding won't be perfect. However, by carefully following these rules, we can make our conclusions more reliable, accurate, and honest. The aim is to help you think in a disciplined way, not to force strict rules, because real research always involves applying ideal standards to studies and information that are never perfect.

1.1.2 Defining Scientific Research in the Social Sciences

"Scientific research," as described here, is an ideal standard that all actual studies, whether quantitative or qualitative, try to reach. No matter the style, scientific research design always has four main characteristics:

  1. The goal is to discover something new (inference): Scientific research aims to learn things (descriptive or explanatory inferences) from observed facts. It's not enough to just collect facts; scientific research means going beyond those facts to understand something broader that isn't directly seen. This includes:

    • Descriptive inference: Learning about unknown facts from the facts you've observed.

    • Causal inference: Learning about cause-and-effect relationships from the data.
      The idea is always to draw conclusions that go beyond just the specific things you looked at.

  2. The steps are public: Scientific research uses clear, organized, and openly shared methods for collecting and analyzing data. This transparency means anyone can check how reliable the research is. Because the methods are public, other scholars can judge the work, learn from it, and even try to repeat it. This is different from research where the methods are kept secret or vague.

  3. The conclusions are not 100% certain: Discovering new knowledge is never perfect. It's impossible to get perfectly certain answers from information that isn't perfectly certain. Recognizing and reporting how uncertain your conclusions are is a key part of all scientific knowledge. Without knowing how sure (or unsure) you are, any descriptions or causal explanations about the real world can't be properly understood.

  4. The method is the core (content is the method): The true meaning of "science" lies in its methods and rules for drawing conclusions, not in what it studies. These methods can be used to study almost anything. As one famous scholar said, "the unity of all science consists alone in its method, not in its material." (This means science is defined by how you discover things, not what you discover).

These four points also mean that science works best as a team effort (social enterprise). Every researcher has limitations and will make mistakes, but because scientific work is public and shared, others in the community are likely to find and correct those errors. Research is a valuable contribution when it deals with concerns of other scholars and uses public, consistent methods to draw conclusions.

1.1.3 Science and Complexity

Social science tries to understand social situations that often seem very complicated. However, how "complex" something seems actually depends on how well we can simplify it by clearly defining what we're looking at and what we think explains it. This simplification ability is related to how good our existing theories are. Scientific methods are useful for both simple and complex events. While complexity might make our conclusions less certain, it doesn't make the study less scientific. In fact, the rules of scientific reasoning are most helpful precisely when you have limited information, imperfect tools, and unclear relationships.

Even seemingly unique and complex events, like the fall of the Roman Empire or the extinction of dinosaurs, can be studied scientifically. One way is to look for general rules by thinking of these unique events as examples of a broader category. Another way is to do counterfactual analysis—which means imagining what would have happened if certain conditions were changed. For example, the theory about dinosaurs dying out because of a meteorite collision (the Alvarez hypothesis) suggests observable things we should find, like a rare element called iridium in geological layers from that time. This allows us to test a hypothesis even for a unique event.

Ultimately, scientific generalizations are useful for unusual events if they lead to observable implications—things we can actually look for and check. A hypothesis isn't considered definitely correct until it has passed many difficult real-world tests and, ideally, predicts things we hadn't observed before ("new facts"). Research design, especially in making theories, collecting data, and using data better, is extremely important even for very complex things. The more observable implications of a theory you collect data on, the better your study will be.

1.2 MAJOR COMPONENTS OF RESEARCH DESIGN

Good social science research is a creative process that happens within a structured scientific framework. A good social scientist understands that research design is not just a rigid plan; they need to be flexible enough to change their views, ask new questions, adjust their designs, and even collect different types of data if needed. However, for the findings to be valid and accepted, all these changes must follow explicit procedures that align with the rules of scientific reasoning. It's an ongoing process where the original plans often don't perfectly match the data, leading to adjustments in questions or theories.

Research design can be broken down into four main parts:

  1. The research question (what you want to find out)

  2. The theory (your educated guess about why)

  3. The data (the information you collect)

  4. How you use the data (how you analyze and interpret it)

These parts don't necessarily happen in a strict order; for example, qualitative researchers might start by collecting data. Understanding each component helps researchers make smart choices when faced with practical limits, making their studies as good as possible.

1.2.1 Improving Research Questions

Choosing a research topic often involves personal interests and a bit of a "creative intuition," as philosopher Karl Popper suggested. There aren't strict rules for picking a topic, unlike rules for designing surveys or conducting fieldwork. While personal reasons for choosing a topic are fine, to make a real contribution to social science, the research methods and rules of scientific reasoning are what truly improve the study. From an academic viewpoint, personal reasons alone aren't enough to justify a topic.

Ideally, all social science research projects should meet two main conditions to be most valuable to the academic community:

  1. Be "important" in the real world: The question should matter for political, social, or economic life, significantly affecting many people or helping us understand and predict useful or harmful events. This judgment primarily comes from society.

  2. Make a specific contribution to existing academic work: The project should help us collectively build better scientific explanations. This could involve describing things accurately, making critical observations, or summarizing history, which are all necessary steps before explaining causes.

Social scientists have plenty of important real-world issues to study (like wars or poverty), but good tools for understanding them are rare. Brilliant ideas alone aren't enough; every idea (hypothesis) needs to be tested with evidence to add to our knowledge. Making an academic contribution means clearly placing your research within what others have already studied, so you understand the current knowledge, avoid repeating work, and ensure your work is relevant to other scholars. Contributions can come in many forms:

  1. Studying important ideas that haven't been systematically investigated yet.

  2. Checking if widely accepted ideas are actually false or haven't been well-proven.

  3. Helping to resolve debates in academic literature or adding more evidence to one side.

  4. Examining or questioning assumptions that are usually taken for granted.

  5. Systematically studying important topics that have been ignored.

  6. Applying existing theories or evidence from one area of study to solve a problem in another, seemingly unrelated area.

Balancing these two criteria—real-world importance and academic contribution—is vital. Focusing too much on academic literature can lead to questions that aren't very useful in the real world, while ignoring academic frameworks can lead to sloppy work. The best research bridges both, improving our understanding of the real world using scientific methods and advancing academic theories. The research design process should always aim for both, no matter where you start.

1.2.2 Improving Theory

A social science theory is a careful and precise guess about the answer to your research question. It explains why the answer might be correct and leads to more specific ideas (hypotheses) that can be tested. A good theory must also fit with what we already know from previous evidence. As one scholar put it, "A theory that ignores existing evidence is an oxymoron" (meaning it's a contradiction in terms).

To make your theory better, especially before you collect and analyze your data, here are some important guidelines:

  1. It must be testable (falsifiable): Your theory should be able to be proven wrong by evidence. If you can't imagine any evidence that would show your theory is incorrect, then it's not a true scientific theory. You need to be able to answer: "What information would show me that I'm wrong?"

  2. Generate many observable implications: Design your theory so it leads to as many different things you can actually observe as possible. This allows for more ways to test your theory using various types of data. The more tests it goes through and survives, the stronger the evidence supporting it.

  3. Be specific and clear (concreteness): State your theories and hypotheses precisely. Vague statements only make things confusing. Theories that are specific and make clear predictions are easier to disprove, and therefore, they are better scientific theories.

The idea of parsimony (that simpler theories are more likely to be true) is sometimes discussed. This concept assumes that the world is simple. It might be good in fields like physics, but not always in social sciences. We should only use parsimony if we already have good reason to believe the part of the world we're studying is simple. Otherwise, theories should be as complex as the evidence suggests.

If you've already collected data, improving your theory needs to be done carefully. Making quick changes (ad hoc adjustments) to your theory just to make it fit your existing data can be misleading. Generally, it's okay to make a theory less restrictive (meaning it applies to more situations) after looking at your data, because this gives it more chances to be proven wrong. However, it's usually wrong to make your theory more restrictive (narrowing its scope to fit exceptions you found) unless you collect brand new data to test this modified version. Such changes just make it seem like your theory is correct when it was actually proven wrong, without any new real support.

If you can't collect new data, sometimes the best thing to do is admit your original theory was wrong; negative findings can be very useful. You can then suggest other ideas or theories for future research, but you must be clear about how uncertain these suggestions are. Pilot projects (small, preliminary studies) are very helpful. They allow you to collect some initial data, adjust your theory or questions based on what you find, and then collect new data to test the refined theory, avoiding the problem of using the same data for both developing and testing your ideas.

1.2.3 Improving Data Quality

"Data" means any systematically gathered information about the world, whether it's numbers or descriptions. No matter if you collect data for a specific idea or just to explore, certain guidelines help make it better:

  1. Always describe how you got your data: This is the most important rule. If you don't explain exactly how your data was collected (e.g., how you picked people for a survey, what questions you asked, or how you chose specific cases), no one can know if your conclusions are reliable. Being transparent helps ensure your findings are trustworthy.

  2. Collect data on many "observable implications" of your theory: To thoroughly test your theory, gather information on as many different things that your theory predicts as possible, and from various situations. Every piece of information that aligns with your theory makes it stronger. This means:

    • Collecting more observations on the same outcome (e.g., looking at shorter time periods or smaller geographic areas).

    • Collecting information on additional outcomes (dependent variables) that your theory might also predict (e.g., if your theory is about deterring attacks, also look at whether threats themselves are deterred).

    • Comparing your theory in similar situations (e.g., how deterrence works in international politics versus how it works among competing businesses) can also give insights, even if not directly applicable.

  3. Make sure your measurements are valid: "Validity" means you are truly measuring what you intend to measure. It's best to stick closely to what you can actually observe and avoid relying on concepts that are hard to see or measure directly. For example, if someone says "I don't know" in an interview, you've validly measured that they said "I don't know." What they really meant by that (e.g., ignorance vs. a subtle protest) is a harder, less valid measurement.

  4. Ensure your data-collection methods are reliable: "Reliability" means that if you use the same method in the same way, you should get the same result every time, assuming the thing you're measuring hasn't changed. Explicit procedures help different researchers get the same results, making their work comparable (e.g., having multiple people interpret qualitative data using the same rules).

  5. All data and analyses should be replicable: Your research should be described in enough detail that another researcher could gather the same data and follow your reasoning to reach your conclusions. Replicability is crucial for checking your methods, even if no one actually repeats your study. For number-based research, this often means providing your dataset so others can re-do your analysis. For qualitative research, it means providing detailed source information (like footnotes) and, if possible, allowing access to your raw notes or interviews. While perfect replication might be tough (e.g., for historical events), the commitment to transparency makes research more scientific. Large-scale projects, like the decades-long replication of the "Middletown" studies, show what's possible.

1.2.4 Improving the Use of Existing Data

While getting new and better data is usually best for solving data problems, it's not always possible. Social scientists often have to work with existing data that might have flaws. Learning how to better use data that's already been collected is a big part of statistical methods and is a key contribution of using statistics in social science. The clear rules from statistical studies also apply to qualitative research. Here are some brief guidelines for using existing data better:

  1. Aim for "unbiased" conclusions: You want your conclusions to be correct on average if you were to apply your methods many times. Even if each individual study might not be perfectly accurate due to small errors, an "unbiased" method won't systematically lean the results in one wrong direction. Achieving unbiased conclusions depends on both how data was originally collected and how it's used later. It's always best to foresee problems before collecting data. When using existing data, you need to be very careful to check for biases that might have been missed during original collection. Two common biases are:

    • Selection bias: This happens when observations (cases) are chosen in a way that unfairly represents the group they came from. For instance, only picking cases that support your theory is a clear example, but it can be more subtle.

    • Omitted variable bias: This occurs when you leave out an important factor (control variable) that influences both what you're trying to explain and your supposed cause, making it seem like there's a connection when there might not be.

  2. Maximize efficiency: This means using all your data and all the relevant information within it to get the most out of it for drawing conclusions. For example, if data is available for small geographical areas, you should use it at that detailed level, not just as a big national total. Even if the smaller details have more uncertainty, they still contain valuable information that can help you understand your theory.

1.3 THEMES OF THIS VOLUME

This section highlights four important running themes in developing research designs:

1.3.1 Using Observable Implications to Connect Theory and Data

Every good theory must have predictions about what you should see if the theory is correct. These observable implications (what you expect to observe) of your theory should guide how you collect data and help you tell what facts are important versus irrelevant. Theory and actual research must be closely linked: research without a guiding theory won't succeed, and a theory without observable predictions is useless. For any theory, you should ask: "What would I expect to see if this theory were true?" And for any observations, you should ask: "Are these observations relevant to my theory's predictions, and what do they tell me about whether my theory is correct?" In social science, your theory's predictions and your observations must fit together. Social science conclusions aren't reliable unless they're built on a strong connection between theory and data, created by carefully thinking about and checking the theory's observable implications.

1.3.2 Maximizing Leverage

Maximizing leverage in social science means trying to explain as much as possible using as little information as possible. You have high leverage when you can explain a complex outcome with just one or a few variables, or when you can explain many different outcomes with just one or a few variables. In general, social sciences, especially qualitative studies, often have low leverage, meaning you need many variables to explain only a little. The goal of research should be to increase this leverage. You can do this by:

  1. Making your theory better so it predicts more observable things.

  2. Improving your data collection so you can actually observe and use more of those predictions.

  3. Improving how you use your existing data to extract more predictions from it.

This idea is different from "parsimony" (which is an assumption that the world itself is simple). Researchers should regularly list all possible things their theory predicts that could be observed in their data or in other data. It's often better to test these new predictions with new or different data, such as data from other types of groups, other aspects of the same groups, different levels of detail (like local vs. national), or different time periods. The more evidence you find that supports your theory across various situations, the stronger your explanation becomes, and the more confidence everyone should have in your conclusions. Even data from different levels of analysis can provide useful information for evaluating a theory, because all observable implications add to its truthfulness.

1.3.3 Reporting Uncertainty

All knowledge and conclusions—in both quantitative and qualitative research—are always uncertain. Both ways of measuring things can have errors, even if those errors come from different sources. A major problem in qualitative research is that often researchers don't provide good estimates of how uncertain their conclusions are. You can make valid conclusions even with limited information by following these rules, but you shouldn't make big, sweeping claims based on weak data. The point isn't that reliable conclusions are impossible in qualitative research, but that you must always report a reasonable estimate of how sure you are about each of your conclusions. One way to think about uncertainty, especially when precise numbers are hard to get, is to ask yourself: "How much of your own money would you bet on this conclusion, and what odds would you expect?"

1.3.4 Thinking like a Social Scientist: Skepticism and Rival Hypotheses

Because causal conclusions are uncertain, good social scientists don't just accept them easily. When someone claims "A causes B," a social scientist will immediately question whether that connection is truly a cause-and-effect relationship. It's easy to question others' research, but it's even more important to question your own. There are many reasons to be skeptical of a causal story, even if it sounds good at first glance. For example, if a newspaper says Japanese people eat less red meat and have fewer heart attacks than Americans, and suggests eating too much steak causes heart disease, a skeptical social scientist would ask:

  • How accurate is the data? (How do they know about eating habits? What group was studied? Are heart attack definitions the same in both countries?)

  • What else could explain this? (Are there other diet differences, genetic factors, or lifestyle choices that might be responsible?)

  • Could the causation be reversed? (Could not having a heart attack make people eat less red meat later in life?)

The goal isn't to disprove medical studies but to show how social scientists approach causal claims: with skepticism and a constant

1 The Science in Social Science

1.1 Introduction

This book is all about how to do research in social sciences so you can figure out reliable answers about how people and groups behave. Even though it talks a lot about political science, the ideas are useful for many fields like sociology (studying society), anthropology (studying human cultures), economics (studying money and resources), psychology (studying the mind), and even things like legal issues or education research. The main goal is very practical: to show you how to ask good research questions and design your studies so you can get trustworthy conclusions about why things happen (descriptive inference) or what causes what (causal inference). It focuses on the basic way of thinking that all social science research shares.

1.1.1 Two Styles of Research, One Logic of Inference

Even though people talk about "quantitative" (using numbers) and "qualitative" (using descriptions) research as very different, they actually use the same fundamental way of thinking to figure things out. Their differences are mostly about style or how they get specific information. Quantitative research uses numbers, math, and statistics. It tries to measure things precisely with numbers, look for general patterns or causes, and make sure others can repeat its steps easily. Qualitative research, on the other hand, doesn't use numbers. It often looks at a small number of specific situations, uses in-depth interviews or detailed historical studies, explains things in words, and tries to give a full picture of an event or group. Both types can gather a huge amount of information.

Historically, there have been big arguments in social sciences between studying individual cases versus using statistics, or between "scientific" (quantitative) methods and "historical" (qualitative) ways. But this book argues these differences are not that deep. All strong research comes from the same basic rules of figuring things out, which means both quantitative and qualitative methods can be structured and scientific. The best research often combines parts of both, like studies that mix number analysis with detailed case stories.

The rules for doing scientific research explained here apply to any study that wants to find out facts about the real world. This is what makes social science different from just casual observations. This approach assumes we can only know some things about the world, and even then, our understanding won't be perfect. However, by carefully following these rules, we can make our conclusions more reliable, accurate, and honest. The aim is to help you think in a disciplined way, not to force strict rules, because real research always involves applying ideal standards to studies and information that are never perfect.

1.1.2 Defining Scientific Research in the Social Sciences

"Scientific research," as described here, is an ideal standard that all actual studies, whether quantitative or qualitative, try to reach. No matter the style, scientific research design always has four main characteristics:

  1. The goal is to discover something new (inference): Scientific research aims to learn things (descriptive or explanatory inferences) from observed facts. It's not enough to just collect facts; scientific research means going beyond those facts to understand something broader that isn't directly seen. This includes:

    • Descriptive inference: Learning about unknown facts from the facts you've observed.

    • Causal inference: Learning about cause-and-effect relationships from the data.
      The idea is always to draw conclusions that go beyond just the specific things you looked at.

  2. The steps are public: Scientific research uses clear, organized, and openly shared methods for collecting and analyzing data. This transparency means anyone can check how reliable the research is. Because the methods are public, other scholars can judge the work, learn from it, and even try to repeat it. This is different from research where the methods are kept secret or vague.

  3. The conclusions are not 100% certain: Discovering new knowledge is never perfect. It's impossible to get perfectly certain answers from information that isn't perfectly certain. Recognizing and reporting how uncertain your conclusions are is a key part of all scientific knowledge. Without knowing how sure (or unsure) you are, any descriptions or causal explanations about the real world can't be properly understood.

  4. The method is the core (content is the method): The true meaning of "science" lies in its methods and rules for drawing conclusions, not in what it studies. These methods can be used to study almost anything. As one famous scholar said, "the unity of all science consists alone in its method, not in its material." (This means science is defined by how you discover things, not what you discover).

These four points also mean that science works best as a team effort (social enterprise). Every researcher has limitations and will make mistakes, but because scientific work is public and shared, others in the community are likely to find and correct those errors. Research is a valuable contribution when it deals with concerns of other scholars and uses public, consistent methods to draw conclusions.

1.1.3 Science and Complexity

Social science tries to understand social situations that often seem very complicated. However, how "complex" something seems actually depends on how well we can simplify it by clearly defining what we're looking at and what we think explains it. This simplification ability is related to how good our existing theories are. Scientific methods are useful for both simple and complex events. While complexity might make our conclusions less certain, it doesn't make the study less scientific. In fact, the rules of scientific reasoning are most helpful precisely when you have limited information, imperfect tools, and unclear relationships.

Even seemingly unique and complex events, like the fall of the Roman Empire or the extinction of dinosaurs, can be studied scientifically. One way is to look for general rules by thinking of these unique events as examples of a broader category. Another way is to do counterfactual analysis—which means imagining what would have happened if certain conditions were changed. For example, the theory about dinosaurs dying out because of a meteorite collision (the Alvarez hypothesis) suggests observable things we should find, like a rare element called iridium in geological layers from that time. This allows us to test a hypothesis even for a unique event.

Ultimately, scientific generalizations are useful for unusual events if they lead to observable implications—things we can actually look for and check. A hypothesis isn't considered definitely correct until it has passed many difficult real-world tests and, ideally, predicts things we hadn't observed before ("new facts"). Research design, especially in making theories, collecting data, and using data better, is extremely important even for very complex things. The more observable implications of a theory you collect data on, the better your study will be.

1.2 MAJOR COMPONENTS OF RESEARCH DESIGN

Good social science research is a creative process that happens within a structured scientific framework. A good social scientist understands that research design is not just a rigid plan; they need to be flexible enough to change their views, ask new questions, adjust their designs, and even collect different types of data if needed. However, for the findings to be valid and accepted, all these changes must follow explicit procedures that align with the rules of scientific reasoning. It's an ongoing process where the original plans often don't perfectly match the data, leading to adjustments in questions or theories.

Research design can be broken down into four main parts:

  1. The research question (what you want to find out)

  2. The theory (your educated guess about why)

  3. The data (the information you collect)

  4. How you use the data (how you analyze and interpret it)

These parts don't necessarily happen in a strict order; for example, qualitative researchers might start by collecting data. Understanding each component helps researchers make smart choices when faced with practical limits, making their studies as good as possible.

1.2.1 Improving Research Questions

Choosing a research topic often involves personal interests and a bit of a "creative intuition," as philosopher Karl Popper suggested. There aren't strict rules for picking a topic, unlike rules for designing surveys or conducting fieldwork. While personal reasons for choosing a topic are fine, to make a real contribution to social science, the research methods and rules of scientific reasoning are what truly improve the study. From an academic viewpoint, personal reasons alone aren't enough to justify a topic.

Ideally, all social science research projects should meet two main conditions to be most valuable to the academic community:

  1. Be "important" in the real world: The question should matter for political, social, or economic life, significantly affecting many people or helping us understand and predict useful or harmful events. This judgment primarily comes from society.

  2. Make a specific contribution to existing academic work: The project should help us collectively build better scientific explanations. This could involve describing things accurately, making critical observations, or summarizing history, which are all necessary steps before explaining causes.

Social scientists have plenty of important real-world issues to study (like wars or poverty), but good tools for understanding them are rare. Brilliant ideas alone aren't enough; every idea (hypothesis) needs to be tested with evidence to add to our knowledge. Making an academic contribution means clearly placing your research within what others have already studied, so you understand the current knowledge, avoid repeating work, and ensure your work is relevant to other scholars. Contributions can come in many forms:

  1. Studying important ideas that haven't been systematically investigated yet.

  2. Checking if widely accepted ideas are actually false or haven't been well-proven.

  3. Helping to resolve debates in academic literature or adding more evidence to one side.

  4. Examining or questioning assumptions that are usually taken for granted.

  5. Systematically studying important topics that have been ignored.

  6. Applying existing theories or evidence from one area of study to solve a problem in another, seemingly unrelated area.

Balancing these two criteria—real-world importance and academic contribution—is vital. Focusing too much on academic literature can lead to questions that aren't very useful in the real world, while ignoring academic frameworks can lead to sloppy work. The best research bridges both, improving our understanding of the real world using scientific methods and advancing academic theories. The research design process should always aim for both, no matter where you start.

1.2.2 Improving Theory

A social science theory is a careful and precise guess about the answer to your research question. It explains why the answer might be correct and leads to more specific ideas (hypotheses) that can be tested. A good theory must also fit with what we already know from previous evidence. As one scholar put it, "A theory that ignores existing evidence is an oxymoron" (meaning it's a contradiction in terms).

To make your theory better, especially before you collect and analyze your data, here are some important guidelines:

  1. It must be testable (falsifiable): Your theory should be able to be proven wrong by evidence. If you can't imagine any evidence that would show your theory is incorrect, then it's not a true scientific theory. You need to be able to answer: "What information would show me that I'm wrong?"

  2. Generate many observable implications: Design your theory so it leads to as many different things you can actually observe as possible. This allows for more ways to test your theory using various types of data. The more tests it goes through and survives, the stronger the evidence supporting it.

  3. Be specific and clear (concreteness): State your theories and hypotheses precisely. Vague statements only make things confusing. Theories that are specific and make clear predictions are easier to disprove, and therefore, they are better scientific theories.

The idea of parsimony (that simpler theories are more likely to be true) is sometimes discussed. This concept assumes that the world is simple. It might be good in fields like physics, but not always in social sciences. We should only use parsimony if we already have good reason to believe the part of the world we're studying is simple. Otherwise, theories should be as complex as the evidence suggests.

If you've already collected data, improving your theory needs to be done carefully. Making quick changes (ad hoc adjustments) to your theory just to make it fit your existing data can be misleading. Generally, it's okay to make a theory less restrictive (meaning it applies to more situations) after looking at your data, because this gives it more chances to be proven wrong. However, it's usually wrong to make your theory more restrictive (narrowing its scope to fit exceptions you found) unless you collect brand new data to test this modified version. Such changes just make it seem like your theory is correct when it was actually proven wrong, without any new real support.

If you can't collect new data, sometimes the best thing to do is admit your original theory was wrong; negative findings can be very useful. You can then suggest other ideas or theories for future research, but you must be clear about how uncertain these suggestions are. Pilot projects (small, preliminary studies) are very helpful. They allow you to collect some initial data, adjust your theory or questions based on what you find, and then collect new data to test the refined theory, avoiding the problem of using the same data for both developing and testing your ideas.

1.2.3 Improving Data Quality

"Data" means any systematically gathered information about the world, whether it's numbers or descriptions. No matter if you collect data for a specific idea or just to explore, certain guidelines help make it better:

  1. Always describe how you got your data: This is the most important rule. If you don't explain exactly how your data was collected (e.g., how you picked people for a survey, what questions you asked, or how you chose specific cases), no one can know if your conclusions are reliable. Being transparent helps ensure your findings are trustworthy.

  2. Collect data on many "observable implications" of your theory: To thoroughly test your theory, gather information on as many different things that your theory predicts as possible, and from various situations. Every piece of information that aligns with your theory makes it stronger. This means:

    • Collecting more observations on the same outcome (e.g., looking at shorter time periods or smaller geographic areas).

    • Collecting information on additional outcomes (dependent variables) that your theory might also predict (e.g., if your theory is about deterring attacks, also look at whether threats themselves are deterred).

    • Comparing your theory in similar situations (e.g., how deterrence works in international politics versus how it works among competing businesses) can also give insights, even if not directly applicable.

  3. Make sure your measurements are valid: "Validity" means you are truly measuring what you intend to measure. It's best to stick closely to what you can actually observe and avoid relying on concepts that are hard to see or measure directly. For example, if someone says "I don't know" in an interview, you've validly measured that they said "I don't know." What they really meant by that (e.g., ignorance vs. a subtle protest) is a harder, less valid measurement.

  4. Ensure your data-collection methods are reliable: "Reliability" means that if you use the same method in the same way, you should get the same result every time, assuming the thing you're measuring hasn't changed. Explicit procedures help different researchers get the same results, making their work comparable (e.g., having multiple people interpret qualitative data using the same rules).

  5. All data and analyses should be replicable: Your research should be described in enough detail that another researcher could gather the same data and follow your reasoning to reach your conclusions. Replicability is crucial for checking your methods, even if no one actually repeats your study. For number-based research, this often means providing your dataset so others can re-do your analysis. For qualitative research, it means providing detailed source information (like footnotes) and, if possible, allowing access to your raw notes or interviews. While perfect replication might be tough (e.g., for historical events), the commitment to transparency makes research more scientific. Large-scale projects, like the decades-long replication of the "Middletown" studies, show what's possible.

1.2.4 Improving the Use of Existing Data

While getting new and better data is usually best for solving data problems, it's not always possible. Social scientists often have to work with existing data that might have flaws. Learning how to better use data that's already been collected is a big part of statistical methods and is a key contribution of using statistics in social science. The clear rules from statistical studies also apply to qualitative research. Here are some brief guidelines for using existing data better:

  1. Aim for "unbiased" conclusions: You want your conclusions to be correct on average if you were to apply your methods many times. Even if each individual study might not be perfectly accurate due to small errors, an "unbiased" method won't systematically lean the results in one wrong direction. Achieving unbiased conclusions depends on both how data was originally collected and how it's used later. It's always best to foresee problems before collecting data. When using existing data, you need to be very careful to check for biases that might have been missed during original collection. Two common biases are:

    • Selection bias: This happens when observations (cases) are chosen in a way that unfairly represents the group they came from. For instance, only picking cases that support your theory is a clear example, but it can be more subtle.

    • Omitted variable bias: This occurs when you leave out an important factor (control variable) that influences both what you're trying to explain and your supposed cause, making it seem like there's a connection when there might not be.

  2. Maximize efficiency: This means using all your data and all the relevant information within it to get the most out of it for drawing conclusions. For example, if data is available for small geographical areas, you should use it at that detailed level, not just as a big national total. Even if the smaller details have more uncertainty, they still contain valuable information that can help you understand your theory.

1.3 THEMES OF THIS VOLUME

This section highlights four important running themes in developing research designs:

1.3.1 Using Observable Implications to Connect Theory and Data

Every good theory must have predictions about what you should see if the theory is correct. These observable implications (what you expect to observe) of your theory should guide how you collect data and help you tell what facts are important versus irrelevant. Theory and actual research must be closely linked: research without a guiding theory won't succeed, and a theory without observable predictions is useless. For any theory, you should ask: "What would I expect to see if this theory were true?" And for any observations, you should ask: "Are these observations relevant to my theory's predictions, and what do they tell me about whether my theory is correct?" In social science, your theory's predictions and your observations must fit together. Social science conclusions aren't reliable unless they're built on a strong connection between theory and data, created by carefully thinking about and checking the theory's observable implications.

1.3.2 Maximizing Leverage

Maximizing leverage in social science means trying to explain as much as possible using as little information as possible. You have high leverage when you can explain a complex outcome with just one or a few variables, or when you can explain many different outcomes with just one or a few variables. In general, social sciences, especially qualitative studies, often have low leverage, meaning you need many variables to explain only a little. The goal of research should be to increase this leverage. You can do this by:

  1. Making your theory better so it predicts more observable things.

  2. Improving your data collection so you can actually observe and use more of those predictions.

  3. Improving how you use your existing data to extract more predictions from it.

This idea is different from "parsimony" (which is an assumption that the world itself is simple). Researchers should regularly list all possible things their theory predicts that could be observed in their data or in other data. It's often better to test these new predictions with new or different data, such as data from other types of groups, other aspects of the same groups, different levels of detail (like local vs. national), or different time periods. The more evidence you find that supports your theory across various situations, the stronger your explanation becomes, and the more confidence everyone should have in your conclusions. Even data from different levels of analysis can provide useful information for evaluating a theory, because all observable implications add to its truthfulness.

1.3.3 Reporting Uncertainty

All knowledge and conclusions—in both quantitative and qualitative research—are always uncertain. Both ways of measuring things can have errors, even if those errors come from different sources. A major problem in qualitative research is that often researchers don't provide good estimates of how uncertain their conclusions are. You can make valid conclusions even with limited information by following these rules, but you shouldn't make big, sweeping claims based on weak data. The point isn't that reliable conclusions are impossible in qualitative research, but that you must always report a reasonable estimate of how sure you are about each of your conclusions. One way to think about uncertainty, especially when precise numbers are hard to get, is to ask yourself: "How much of your own money would you bet on this conclusion, and what odds would you expect?"

1.3.4 Thinking like a Social Scientist: Skepticism and Rival Hypotheses

Because causal conclusions are uncertain, good social scientists don't just accept them easily. When someone claims "A causes B," a social scientist will immediately question whether that connection is truly a cause-and-effect relationship. It's easy to question others' research, but it's even more important to question your own. There are many reasons to be skeptical of a causal story, even if it sounds good at first glance. For example, if a newspaper says Japanese people eat less red meat and have fewer heart attacks than Americans, and suggests eating too much steak causes heart disease, a skeptical social scientist would ask:

  • How accurate is the data? (How do they know about eating habits? What group was studied? Are heart attack definitions the same in both countries?)

  • What else could explain this? (Are there other diet differences, genetic factors, or lifestyle choices that might be responsible?)

  • Could the causation be reversed? (Could not having a heart attack make people eat less red meat later in life?)

The goal isn't to disprove medical studies but to show how social scientists approach causal claims: with skepticism and a constant