Lessons 07–09: Causality, Experimental Designs, and Research Sources

A set of vocabulary flashcards summarizing key terms from Lessons 07–09 on causality, experimental design, and research sources.

Causality

A relationship in which one variable directly produces a change in another variable.

Association (Rule of Causality)

The predictor and outcome variables must covary.

Precedence (Rule of Causality)

The cause must occur before the effect.

Parsimoniousness (Rule of Causality)

Alternative explanations have been ruled out.

Plausibility (Rule of Causality)

The proposed mechanism is scientifically reasonable.

Regular Causality

A direct, one-way cause-and-effect relationship.

Reverse Causality

The presumed effect actually causes the presumed cause.

Bidirectional Causality

Two variables influence each other mutually.

Third-Variable Causality

An unmeasured variable causes changes in both variables of interest.

Complex Causal Network

Multiple interacting causes produce an outcome.

Experimental Manipulation

Deliberately changing an independent variable to observe its effect on a dependent variable.

Person Variable

A characteristic (e.g., personality) that cannot be manipulated by the researcher.

Situation Variable

A temporary state (e.g., mood) that can be experimentally manipulated.

Institutional Review Board (IRB)

Committee that evaluates and oversees ethical aspects of human research.

Belmont Report

Foundational document outlining Respect for Persons, Beneficence, and Justice in human research ethics.

Respect for Persons

Belmont principle emphasizing informed consent and autonomy.

Beneficence

Belmont principle requiring maximization of benefits and minimization of harm.

Justice (Ethics)

Belmont principle calling for equitable distribution of research burdens and benefits.

Institutional Animal Care and Use Committee (IACUC)

Body that oversees the ethical treatment of animals in research.

Confound

An uncontrolled variable that varies with the independent variable and may influence the outcome.

Expectancy Effect

Change in participants’ or experimenters’ behavior based on expectations about the study.

Placebo Effect

Improvement resulting from participants’ belief they are receiving treatment.

Observer Bias

Researcher expectations systematically influence data recording or interpretation.

Social Desirability Bias

Tendency of participants to respond in a manner viewed favorably by others.

Attrition

Unequal dropout rates between study groups that can bias results.

True Experiment

Study featuring manipulation of an IV and random assignment to conditions.

Quasi-Experiment

Study with manipulation but no random assignment.

Pre-Post Study

Within-subject design lacking a control group; measures participants before and after a treatment.

Between-Subjects Quasi-Experiment

Non-random comparison of treatment and control groups.

Clinical Trial

Medical experiment on human patients testing interventions’ safety or efficacy.

Simple Laboratory Experiment

Highly controlled study conducted in a lab or field setting with one main manipulation.

Factorial Design

Experiment testing two or more independent variables simultaneously.

2×2 Design

Factorial design with two independent variables, each at two levels.

Crossover Design

Participants receive both treatment and control in different periods; order is randomized.

Internal Validity

Degree to which a study convincingly demonstrates a causal relationship.

Carryover Effect

Influence of one treatment condition on subsequent conditions in within-subject designs.

Primary Research Article

Original empirical study reporting new data (e.g., clinical trial, experiment).

Secondary Research Article

Work that summarizes or analyzes multiple primary studies (e.g., review).

Tertiary Research Article

Condensed overview intended for a broad audience (e.g., guidelines, health websites).

Narrative Literature Review

Non-systematic summary and interpretation of existing research on a topic.

Publication Bias

Tendency for studies with significant results to be more likely published.

Reviewer Bias

Influence of an author’s opinions on which studies are included in a review.

Systematic Literature Review

Review that follows a predefined, transparent method to locate and evaluate studies.

Meta-Analysis

Quantitative technique that combines numerical results from multiple studies.

Effect Size

Standardized measure of the strength of a relationship or treatment effect.

Statistical Power

Probability of detecting a true effect in a study or meta-analysis.

Inclusion/Exclusion Criteria

Predefined rules determining which studies are considered in a systematic review.

Expert Collaboration

Consulting specialists who base recommendations on evidence and consensus.

Bertrand Russell’s Skepticism Principle

Guideline to trust expert consensus unless credible contrary evidence exists.