Experiments, Designs and Controls
Compare laboratory, field, natural and quasi-experimental methods and select a participant design with suitable controls.
How to study A-level Psychology
For every claim, identify the mechanism, supporting evidence, method, alternative explanation, practical implication and justified conclusion.
Core concepts
Concept 1
Laboratory, field, natural and quasi experiments differ in manipulation, setting, control and the strength of causal inference.
Exam cue: Classify an experiment from how the independent variable arose, not merely from its location.
Concept 2
Independent groups, repeated measures and matched pairs designs create different risks from participant variables, order effects and matching difficulty.
Exam cue: Link each design strength or weakness to the actual study context.
Concept 3
Random allocation, counterbalancing, standardisation, control conditions, placebo procedures and blinding address distinct threats.
Exam cue: Name a specific control and explain which alternative explanation it reduces.
Targeted study blocks
Multi-board knowledge
Secure the shared psychological core
Secure the defining features, design choices and controls used across current specifications rather than memorising a single board's study list.
Scientific reasoning
Use evidence before reaching a judgement
Choose the design that best answers the research question, then balance control and causal inference against realism, ethics and participant effects.
Risk pitfalls and guardrails
Assuming every study in a laboratory is a laboratory experiment.
Guardrail: Do not memorise a study as an isolated story or assume that one board's named research and option choices apply nationally.
Confusing random allocation to conditions with random sampling from a population.
Guardrail: Do not memorise a study as an isolated story or assume that one board's named research and option choices apply nationally.
Listing generic strengths without judging the causal claim being made.
Guardrail: Do not memorise a study as an isolated story or assume that one board's named research and option choices apply nationally.
Memory anchors
Laboratory experiment
The researcher manipulates an independent variable in a highly controlled setting.
Field experiment
The researcher manipulates an independent variable in a natural setting.
Natural experiment
The independent variable occurs without researcher manipulation.
Repeated measures
The same participants take part in every condition.
Counterbalancing
Counterbalancing varies condition order to distribute order effects.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which procedural features make a psychology study a laboratory experiment?
A researcher changes background music in a working café and records tips. What type of experiment is this?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
What is Pass Harbor?
Completely free exam prep for 247 UK exams.
- Practice questions
- Flashcards
- Study guides
- Mock exams
- No registration
- No paywall
- Start instantly
“No more expensive exam prep. Quality study tools should be accessible to everyone.”