2.4.6—Research methods

Research methods are the planned ways psychologists collect and analyse evidence, such as experiments, interviews, observations, surveys and case studies. The method must operationalise the variables and fit the kind of claim being made.

Experiments can support causal inference when manipulation, comparison and control are credible. Interviews and observations can reveal meaning and behaviour in context, but researcher influence, sampling and interpretation become central validity questions.

To study whether sleep changes reaction time, an experiment can manipulate sleep opportunity and measure a defined response. To understand how students experience sleep loss, a semi-structured interview may be more informative but cannot alone establish causation.

No method is automatically superior. Identify the research question, the evidence needed, and the trade-off between control, ecological validity, ethics and transferability before judging the design.

Different methods answer different questions: experiments manipulate an independent variable for causal inference; observations record behaviour in a setting; surveys collect standardized self-report; interviews explore accounts in depth; correlational studies measure relationships without manipulation; case studies integrate multiple sources around one bounded case. Selection must fit the claim and access conditions, while ethics, demand characteristics, researcher effects, confounds and external variables limit what can be concluded.