WACE Psychology — Unit 4
Experimental Design — Flashcards & Quiz
Experimental design is the heart of empirical psychology, and WACE Psychology Year 12 Unit 4 expects you to identify independent variables (IV), dependent variables (DV), control variables, and potential confounds. You need to distinguish between-subjects and within-subjects designs and evaluate internal and external validity.
Key Points
- Independent variable (IV): what the experimenter manipulates.
- Dependent variable (DV): what is measured to assess the IV's effect.
- Control variables: held constant to prevent them influencing the DV.
- Confounding variables: uncontrolled factors that could explain the results — the main threat to internal validity.
- Between-subjects design: different participants in each condition. Simpler but requires more participants.
- Within-subjects (repeated measures): same participants in all conditions. More efficient but risks order effects (solved by counterbalancing).
Common Mistakes to Avoid
- Confusing the IV (cause) with the DV (effect).
- Forgetting about confounds when evaluating validity.
- Using "random sampling" (how participants are chosen) interchangeably with "random allocation" (how they're assigned to conditions).
- Missing order effects in within-subjects designs.
- Claiming a study is valid just because it found a result — internal validity requires controlled confounds.
Exam Strategy
SCSA Unit 4 research methods questions give you an experimental scenario and ask you to identify variables, design type, and threats to validity. Method: (1) identify IV and DV, (2) name the design type, (3) list potential confounds, (4) evaluate internal and external validity, (5) suggest improvements. Diagrams of design setup help.
Sample Flashcards
Q1: Compare independent groups, repeated measures and matched pairs experimental designs.
Independent groups (between-subjects): different participants in each condition. Strength: no order effects. Limitation: individual differences between groups may confound results; requires more participants. Repeated measures (within-subjects): the same participants in all conditions. Strength: controls individual differences. Limitation: order effects (fatigue, practice); addressed by counterbalancing. Matched pairs: participants are matched on key variables and then assigned to different conditions. Strength: reduces individual differences without order effects. Limitation: matching is time-consuming and imperfect; difficult to match on all relevant variables.
Sample Quiz Questions
Q1: In a repeated measures design, different participants are used in each experimental condition.
Answer: FALSE
In a repeated measures (within-subjects) design, the same participants are used in all conditions. Different participants in each condition describes an independent groups (between-subjects) design.
Revision Tip
Experimental design terms are vocabulary-heavy — drill a Revizi deck with IV, DV, control variable, confound, validity definitions until recall is instant.
Last updated: March 2026 · 1 flashcards · 1 quiz questions