ap psych research methods

Experiments

A research method where variables are manipulated under controlled conditions to isolate cause-and-effect relationships.

Correlational Studies

A research design that measures the strength and direction of the relationship between two naturally occurring variables without direct manipulation.

Survey Research

A method of gathering self-reported data from a large sample through questionnaires or structured interviews to measure attitudes, opinions, or behaviors.

Naturalistic Observation

Observing and recording subjects' behavior in their natural environment without intervention or manipulation by the researcher.

Case Studies

An in-depth examination of a single individual, group, or unique situation over an extended period to gather rich qualitative detail.

Causation in Research

The principle that cause-and-effect conclusions can only be drawn from experimental designs that manipulate an independent variable and control extraneous factors.

Experimental Controls

Baseline conditions and procedures used to hold extraneous variables constant and eliminate alternative explanations for an outcome.

Independent Variable

The specific factor in an experiment that is deliberately manipulated or changed by the researcher.

Dependent Variable

The outcome factor being measured in an experiment to assess whether it changes in response to the independent variable.

Confounding Variable

An unintended extraneous factor that varies alongside the independent variable, obscuring whether the treatment caused the observed effect.

Control Variable

An extraneous factor that is intentionally kept constant across all experimental conditions to ensure a fair comparison.

Random Selection

A sampling process where every individual in a population has an equal chance of being chosen, ensuring a representative sample for surveys and correlational studies.

Random Assignment

The placement of participants into experimental or control groups by chance, minimizing pre-existing individual differences across conditions.

Internal Validity

The degree to which an experiment accurately measures a true cause-and-effect relationship without interference from confounding variables.

External Validity

The extent to which the results of a study can be generalized beyond the specific sample to real-world settings or broader populations.

Descriptive Statistics

Numerical techniques used to summarize, organize, and describe the basic characteristics of a specific data set.

Inferential Statistics

Numerical procedures used to determine whether sample results can be generalized to a larger population or are statistically significant.

Measures of Central Tendency

Single scores (mean, median, mode) that represent the center or typical value of a data set.

Measures of Variation

Statistics (range, standard deviation) that describe the degree of spread or dispersion among scores in a distribution.

Data Visualization

Graphs such as histograms and scatterplots used to visually display distributions, patterns, or relationships between continuous variables.

Operational Definitions

Precise, measurable descriptions of variables that allow abstract psychological concepts to be tested and quantified consistently.

Replication

The repetition of a study using the same standardized protocols to verify the consistency and reliability of its original findings.

Ethical Constraints

Moral principles and legal mandates that limit how research can be designed and conducted to avoid harm to participants.

Participant Protections

Standard safeguards—including informed consent, protection from harm, confidentiality, and debriefing—that preserve subjects' rights and well-being.

Institutional Governance

Oversights established by the APA, federal regulations, and Institutional Review Boards (IRBs) to review, approve, and monitor scientific studies.