Cambridge A-Level Psychology: Research Methods — Revision Notes (9990)

Related: Paper 2 study guide

Condensed, exam-focused notes for Paper 2 of Cambridge AS & A Level Psychology (9990), 2024-2026 series.

The six research methods

• Experiments (laboratory, field): designs — independent measures, matched pairs, repeated measures; concepts — counterbalancing (addresses order effects in repeated measures), random allocation, order effects.
• Self-reports (questionnaires, interviews).
• Case studies (single participant/unit, studied in detail).
• Observations: overt/covert, participant/non-participant, structured/unstructured, naturalistic/controlled.
• Correlations: positive/negative, strength, co-variables.
• Longitudinal studies (including longitudinal-design experiments).
• For each method: describe its features, evaluate it (reliability/validity/ethics), apply it to a novel scenario — this describe-evaluate-apply pattern recurs across every method.

Methodological concepts

• Variables: identify and operationalise IV and DV in a scenario, not just define the terms.
• Sampling: opportunity, random, volunteer/self-selecting — and implications for generalisability.
• Ethics: humans (informed consent, right to withdraw, deception, confidentiality, debriefing) vs animals (replacement, species, numbers, pain/suffering/distress) — apply the correct set for the scenario.
• Validity (measures what it claims to — ecological validity, demand characteristics, generalisability) vs reliability (consistency — inter-rater, inter-observer, test-retest) — a commonly confused pair.
• Data analysis: mode, median, mean, range, standard deviation, bar charts/histograms/scatter graphs. No calculations or statistical tests beyond this are required.

Paper structure: Section A and Section B

• Section A: short-answer questions on general research methods and on methods relating to a specific Paper 1 core study, plus three short-answer scenario-based questions.
• Section B: a single planning question — plan a study, evaluate some aspects of the plan.

The planning question

• Must include: procedure, how the plan makes the study valid, how it makes it reliable, types of data collected, plus method-specific features (e.g. for a field experiment: IV, DV, controls, experimental design, location).
• Not required at Paper 2: aims/hypotheses in the plan, or evaluation of sample/generalisability or ethics — a deliberate contrast with Paper 4 at A Level, which does require these. Don’t import Paper 4’s fuller requirements into a Paper 2 answer.

Exam technique for this topic

Learn the six methods and the block of methodological concepts as two connected layers: the methods are what a study is, the concepts are what any study can be judged by. When revising Paper 1’s core studies, always note which method each one used, since Section A frequently draws a link between a familiar study and the method that produced it. For the planning question, work from the syllabus’s checklist of general features before adding method-specific detail, and be precise about what Paper 2 does and doesn’t require — adding unnecessary aims, hypotheses or ethical evaluation costs time without earning credit.

Worked example: designing an ethical check

Consider a proposed study observing children’s playground behaviour without their knowledge, to reduce demand characteristics. A strong answer identifies the specific ethical issues this raises for human participants — informed consent (children cannot meaningfully consent, so parental/guardian consent and appropriate debriefing become essential), and privacy (covert observation in a semi-public space raises different considerations from covert observation somewhere clearly private) — rather than giving a generic “ethics is important” comment. If the study instead involved animals, the relevant checklist shifts entirely: replacement (could a non-animal method answer the same question), the specific species used, and procedural concerns such as pain, suffering or distress become the examinable issues instead. Applying the correct ethical framework for the participant type described in the scenario, rather than a single generic ethics checklist, is exactly what this concept tests.

Worked example: validity vs reliability applied

A memory experiment conducted in a quiet laboratory using a standardised word list produces very consistent results across repeated trials — high reliability, since repeating the procedure gives similar results each time. However, because real-world memory rarely involves memorising isolated word lists in silence, the study may lack ecological validity — it may not accurately reflect how memory actually functions in everyday situations, even though its reliability is excellent. This example illustrates why the two concepts must be evaluated separately rather than assumed to move together: a highly reliable study is not automatically a valid one, and building the habit of assessing both independently for any described study is precisely what Section A questions on this concept require.

Self-test

1. Name the three experimental designs and one concept associated with repeated measures.
2. What is the difference between validity and reliability?
3. Name the three sampling techniques on this syllabus.
4. What must a Paper 2 plan include that is NOT required for a Paper 4 plan (or vice versa — name one Paper 4 requirement not needed at Paper 2)?
5. Which section of Paper 2 is the planning question?

Answers: 1. Independent measures, matched pairs, repeated measures; counterbalancing addresses order effects in repeated measures. 2. Validity = whether a study measures what it claims to; reliability = consistency of results. 3. Opportunity, random, volunteer/self-selecting. 4. Paper 4 requires aims, hypotheses, sampling technique and ethics in the plan; Paper 2 does not require these. 5. Section B.

Why the describe-evaluate-apply pattern matters

Applying the same three-part structure — describe, evaluate, apply — to every one of the six research methods, rather than learning each method’s content in a different shape, makes revision far more efficient and produces more consistent exam answers. A candidate who has drilled this pattern can approach an unfamiliar Section A scenario question about, say, longitudinal studies with the same confidence as a well-rehearsed question about experiments, because the underlying structure of what’s being asked (describe the method’s features, evaluate it, apply it to the given scenario) never changes, even though the specific method does.