IB Psychology Research Methodology Glossary

Independent Variable (IV)

The variable that is manipulated by the researcher to observe its effect on the dependent variable.

Dependent Variable (DV)

The variable that is measured to assess the effect of the independent variable.

Operationalization

Defining variables in practical, measurable terms.

Hypothesis

A testable prediction about the relationship between two or more variables.

Null Hypothesis

A prediction that there is no effect or no relationship between variables.

Experimental Design

The way in which participants are allocated to conditions in an experiment (e.g., independent measures, repeated measures, matched pairs).

Control Group

The group in an experiment that does not receive the treatment; used for comparison.

Confounding Variable

An external factor that may affect the dependent variable and confuse the results.

Random Allocation

Assigning participants to experimental groups randomly to reduce bias.

Sampling

The process of selecting participants from the population.

Representative Sample

A sample that accurately reflects the population from which it is drawn.

Ethics

Guidelines for conducting research responsibly and respectfully, including informed consent, confidentiality, and the right to withdraw.

Ecological Validity

The extent to which research findings can be generalized to real-life settings.

Reliability

The consistency of a research study or measuring test.

Validity

The extent to which a test or research study measures what it claims to measure.

Demand Characteristics

Cues in an experiment that may reveal the aim to participants, influencing their behavior.

Researcher Bias

When a researcher's expectations influence the outcome of a study.

Double-Blind Procedure

Neither the participants nor the experimenters know who is receiving the treatment; helps reduce bias.

Quantitative Data

Numerical data that can be measured and analyzed statistically.

Qualitative Data

Descriptive data obtained through methods like interviews or observations.

Triangulation

Using multiple methods or sources to increase the credibility of research findings.

Informed Consent

Participants agreeing to take part in a study with full awareness of the nature and potential risks.

Deception

Withholding information or misleading participants; must be justified and followed by debriefing.

Debriefing

Explaining the true nature and purpose of the study to participants after it concludes.

Random Sampling

Every member of the population has an equal chance of being selected.

Opportunity Sampling

Participants are selected based on availability and willingness to take part.

Stratified Sampling

The population is divided into subgroups (strata), and participants are randomly selected from each subgroup.

Self-selected Sampling

Participants volunteer to take part in the study.

Snowball Sampling

Existing participants recruit future participants from among their acquaintances.

Purposive Sampling

Participants are selected based on specific characteristics or purpose relevant to the study.

Laboratory Experiment

A controlled environment where variables can be manipulated and measured.

Field Experiment

Conducted in a real-life setting, with manipulation of the IV.

Natural Experiment

The IV is not manipulated by the researcher but occurs naturally.

Quasi-Experiment

Participants are grouped based on characteristics that cannot be randomly assigned (e.g., gender).

Case Study

An in-depth investigation of an individual or group over time.

Interview

A method of collecting data through direct questioning.

Structured Interview

Uses a standardized set of questions.

Semi-structured Interview

Includes both fixed and open-ended questions.

Unstructured Interview

More like a guided conversation.

Observation

The researcher watches behavior in a natural or controlled setting.

Participant Observation

The researcher becomes involved in the group being studied.

Non-participant Observation

The researcher observes without becoming involved.

Naturalistic Observation

Takes place in a natural setting without interference.

Controlled Observation

Takes place in a structured and controlled environment.

Inductive Content Analysis

A qualitative method for analyzing interview and textual data by identifying themes.

Descriptive Statistics

Summarizes data (mean, median, mode, standard deviation).

Inferential Statistics

Tests hypotheses and determines if findings can be generalized.

Research Aim

The general purpose or goal of a research study.

Target Population

The group of people the research is intended to represent.

External Validity

The extent to which the results can be generalized beyond the study.

Internal Validity

The extent to which the study accurately establishes a cause-effect relationship.

Inter-rater Reliability

The level of agreement between different observers or raters.

Sampling Bias

Occurs when the sample is not representative of the population, affecting generalizability.

Confirmation Bias

The tendency to search for or interpret information in a way that confirms one's preconceptions.

Publication Bias

The tendency for journals to publish positive or significant findings rather than non-significant results.

Observer Bias

When the researcher's expectations influence their interpretation of the results.

Participant Bias

When participants alter their behavior due to the awareness of being observed.

Social Desirability Bias

When participants respond in a way that they believe is more socially acceptable.

Hindsight Bias

The tendency to see events as having been predictable after they have already occurred.

Cultural Bias

Interpreting and judging phenomena by standards inherent to one's own culture.

Experimenter Expectancy Effect

When the experimenter's expectations influence the outcome of the research.