Research Methods Vocabulary

Flashcards of key vocabulary terms and definitions from the lecture notes.

Evidence-based treatment

A psychotherapy technique whose effectiveness has been supported by empirical research.

Empiricism

The use of verifiable evidence as the basis for conclusions; collecting data systematically and using it to develop, support, or challenge a theory.

Theory

A statement or set of statements that describes general principles about how variables relate to one another.

Hypothesis

A statement of the specific result the researcher expects to observe from a particular study if the theory is accurate.

Data

A set of observations representing the values of some variable, collected from one or more research studies.

Self-correcting

A process in which scientists make their research available for peer review, replication, and critique, with the goal of identifying and correcting errors in the research.

Applied research

Research whose goal is to find a solution to a particular real-world problem.

Basic research

Research whose goal is to enhance the general body of knowledge, without regard for direct application to practical problems.

Confound

A potential alternative explanation for a research finding; a threat to internal validity.

Probabilistic

Describing the empirical method, stating that science is intended to explain a certain proportion (but not necessarily all) of the possible cases.

Availability Heuristic

A bias in intuition, in which people incorrectly estimate the frequency of something, relying predominantly on instances that easily come to mind rather than using all possible evidence in evaluating a conclusion.

Open access

Term referring to a peer-reviewed academic journal that anyone, even the general public, can read without paying for access.

Variable

An attribute that varies, having at least two levels, or values.

Measured variable

A variable in a study whose levels (values) are observed and recorded.

Operational definition

The specific way in which a concept of interest is measured or manipulated as a variable in a study.

Frequency claim

A claim that describes a particular rate or degree of a single variable.

Positive association

An association in which high levels of one variable go with high levels of the other variable, and low levels of one variable go with low levels of the other variable.

Zero association

A lack of systematic association between two variables.

Validity

The appropriateness of a conclusion or decision.

External validity

An indication of how well the results of a study generalize to individuals or contexts besides those in the study itself.

Covariance

The degree to which two variables go together. Also one of three criteria for establishing a causal claim, which states that, in a study's results, the proposed causal variable must vary systematically with changes in the proposed outcome variable.

Temporal precedence

One of three criteria for establishing a causal claim, stating that the proposed causal variable comes first in time, before the proposed outcome variable.

Random assignment

The use of a random method (e.g., flipping a coin) to assign participants into different experimental groups.

Informed consent

The right of research participants to learn about a research project, know its risks and benefits, and decide whether to participate.

Principle of beneficence

An ethical principle from the Belmont Report stating that researchers must take precautions to protect participants from harm and to promote their well-being.

Ordinal scale

A quantitative measurement scale whose levels represent a ranked order, and in which distances between levels are not equal.

Ratio scale

A quantitative measurement scale in which the numerals have equal intervals and the value of zero truly means "none" of the variable being measured.

Reliability

The consistency of the results of a measure.

Interrater reliability

The degree to which two or more coders or observers give consistent ratings of a set of targets.

Content validity

The extent to which a measure captures all parts of a defined construct.

Average inter-item correlation (AIC)

A measure of internal reliability for a set of items; it is the mean of all possible correlations computed between each item and the others.

Open-ended question

A survey question format that allows respondents to answer any way they like.

Likert scale

A survey question format using a rating scale containing multiple response options anchored by the specific terms strongly agree, agree, neither agree nor disagree, disagree, and strongly disagree.

Double-barreled question

A type of question in a survey or poll that is problematic because it asks two questions in one, thereby weakening its construct validity.

Socially desirable responding

Giving answers on a survey (or other self-report measure that make one look better than one really is.

Observer bias

A bias that occurs when observer expectations influence the interpretation of participant behaviors or the outcome of the study.

Population

A larger group from which a sample is drawn; the group to which a study's conclusions are intended to be applied.

Biased sample

A sample in which some members of the population of interest are systematically left out, and therefore the results cannot generalize to the population of interest.

Convenience sampling

Choosing a sample based on those who are easiest to access and readily available; a biased sampling technique.

Cluster sampling

A probability sampling technique in which clusters of participants within the population of interest are selected at random, followed by data collection from all individuals in each cluster.

Quota sampling

A biased sampling technique in which a researcher identifies subsets of the population of interest, sets a target number for each category in the sample, and nonrandomly selects individuals within each category until the quotas are filled.

Mean

An arithmethic average; a measure of central tendency computed from the sum of all the scores in a set of data, divided by 6 the total number of scores.

Effect size

The magnitude, or strength, of a relationship between two or more variables.

Outlier

A score that stands out as either much higher or much lower than most of the other scores in a sample.

Third-variable problem

A plausible alternative explanation for the association between two variables.

Moderator

A variable that, depending on its level, changes the relationship between two other variables.

Longitudinal design

A study in which the same variables are measured in the same people at different points in time.

Control for

Holding a potential third variable at a constant level (statistically or experimentally) while investigating the association between two other variables.

Criterion variable

The variable in a multiple-regression analysis that the researchers are most interested in understanding or predicting.

Mediator

A variable that helps explain the relationship between two other variables.

Control group

A level of an independent variable that is intended to represent "no treatment" or a neutral condition.

Confound

A general term for a potential alternative explanation for a research finding; a threat to internal validity.

Design confound

A threat to internal validity in an experiment in which a second variable happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results.

Selection effect

A threat to internal validity that occurs in an independent-groups design when the kinds of participants at one level of the independent variable are systematically different from those at the other level.

Counterbalancing

Presenting the levels of the independent variable to participants in different sequences to control for order effects.

Demand characteristic

A cue that leads participants to guess a study's hypotheses or goals; a threat to internal validity.

Pilot study

A study completed before (or sometimes after) the study of primary interest, usually to test the effectiveness or characteristics of the manipulations.

One-group, pretest/posttest design

An experiment in which a researcher recruits one group of participants; measures them on a pretest; exposes them to a treatment, intervention, or change; and then measures them on a posttest.

Maturation threat

A threat to internal validity that occurs when an observed change in an experimental group could have emerged more or less spontaneously over time.

Regression threat

A threat to internal validity related to regression to the mean, a phenomenon in which any extreme finding is likely to be closer to its own typical, or mean, level the next time it is measured

Instrumentation threat

A threat to internal validity that occurs when a measuring instrument changes over time.

Double-blind study

A study in which neither the participants nor the researchers who evaluate them know who is in the treatment group and who is in the comparison group.

Placebo effect

A response or effect that occurs when people receiving an experimental treatment experience a change only because they believe they are receiving a valid treatment.

Power

The likelihood that a study will show a statistically significant result when an independent variable truly has an effect in the population; the probability of not making a Type Il error.

Interaction effect

A result from a factorial design, in which the difference in the levels of one independent variable changes, depending on the level of the other independent variable; a difference in differences.

Factorial design

A study in which there are two or more independent variables, or factors.

Parsimony

The degree to which a theory provides the simplest explanation of some phenomenon.

Quasi-experiment

A study similar to an experiment except that the researchers do not have full experimental control

Interrupted time-series design

A quasi-experiment in which participants are measured repeatedly on a dependent variable before, during, and after the "interruption" caused by some event.

Stable-baseline design

A small-N design in which a researcher observes behavior for an extended baseline period before beginning a treatment or other intervention, and continues observing behavior after the intervention.

Replicable

Describing a study whose results have been reproduced when the study was repeated, or replicated.

Conceptual replication

A replication study in which researchers examine the same research question (the same conceptual variables) but use different procedures for operationalizing the variables.

Scientific literature

A series of related studies, conducted by various researchers, that have tested similar variables.

HARKing (hypothesizing after the results are known)

A questionable research practice in which researchers create an after-the-fact hypothesis about an unexpected research result, making it appear as if they predicted it all along.

p-hacking

A family of questionable data analysis techniques, such as adding participants after the results are initially analyzed, looking for outliers, or trying new analyses in order to obtain a p value of just under .05, which can lead to nonreplicable results.

Open data

When psychologists provide their full data set on the Internet so other researchers can reproduce the statistical results or even conduct new analyses on it.

Ecological validity

The extent to which the tasks and manipulations of a study are similar to real-world contexts; an aspect of external validity.

Theory-testing mode

A researcher's intent for a study, testing association claims or causal claims to investigate support for a theory.