How does a case study differ from a laboratory experiment in terms of variable control?

A case study has very low control over variables as it observes naturally occurring phenomena in real-life settings. In contrast, a laboratory experiment involves strict manipulation of an independent variable and control of extraneous factors to establish cause-and-effect.

What is the difference between the 'idiographic' approach of case studies and the 'nomothetic' approach of surveys?

The idiographic approach focuses on the unique, individual details of a single case to gain deep insight. The nomothetic approach, used in surveys, seeks to identify general laws or patterns that apply to large populations through statistical analysis.

Why is a case study considered more ethically flexible than an experiment for studying brain damage?

It is unethical to intentionally cause brain damage in humans for an experiment. Case studies allow researchers to study individuals who have already suffered naturally occurring damage, providing valuable data without violating ethical codes.

What is the 'generalizability' error often associated with case studies?

Because case studies focus on a single individual or a very small, unique group ($N=1$), the findings may not represent the general population. This lack of population validity makes it risky to apply the results to everyone else.

How can researcher bias affect the outcome of a longitudinal case study?

Over a long period, researchers may develop a close personal relationship with the participant. This can lead to a loss of objectivity, where the researcher interprets data in a way that supports their expectations or feelings rather than remaining neutral.

Why is it a mistake to assume a case study can definitively prove a cause-and-effect relationship?

Case studies lack the controlled environment and manipulation of variables necessary to isolate a single cause. While they provide detailed descriptions, they cannot rule out the influence of extraneous variables that might be responsible for the observed behavior.

What does it mean for a case study to be 'longitudinal'?

It means the research is conducted over an extended period of time, allowing the researcher to observe how the participant's behavior or condition develops, improves, or changes as they age or undergo treatment.

Define 'triangulation' in the context of case study research.

Triangulation is the use of multiple methods or data sources (e.g., combining interviews, observations, and medical tests) to study the same phenomenon. This helps to validate the findings by ensuring different types of data point to the same conclusion.

What is 'qualitative data' in a case study?

Qualitative data consists of non-numerical, descriptive information, such as the content of an interview, descriptions of behavior during an observation, or entries in a personal diary, focusing on the 'why' and 'how' of human experience.

How do case studies contribute to the 'nature vs. nurture' debate?

By studying individuals in extreme or unique circumstances (like severe isolation), researchers can observe how much of their development was due to biological factors (nature) versus their environment and upbringing (nurture).

Case Studies in Psychological Research | OCR GCSE Psychology

1. Definition & Core Concepts

A case study is defined not as a single research method, but as a comprehensive research strategy that employs a combination of techniques to gather detailed data.

The primary focus is on a bounded system, such as a specific person, a family, or a small organization, providing a holistic view of their experiences and behaviors.

These studies are typically longitudinal, meaning they take place over an extended period—often years or decades—to track development, recovery, or change over time.

A conceptual diagram showing a central Case Study node receiving data from multiple sources: Interviews, Observations, Clinical Data, and Psychometric Tests.

2. Underlying Principles

The principle of triangulation is central to case studies, where researchers use multiple data sources (e.g., diaries, MRI scans, and interviews) to cross-verify findings and increase internal validity.

Case studies prioritize idiographic understanding, focusing on the unique traits and history of the individual rather than seeking general laws that apply to a whole population.

They are often used when the variable of interest is a rare phenomenon, such as a specific type of brain damage or extreme social isolation, where experimental manipulation would be unethical.

3. Methods & Techniques

Qualitative Data Collection: Researchers often use unstructured interviews and naturalistic observations to capture the 'richness' of the participant's subjective experience.

Quantitative Data Collection: Objective measures such as IQ scores, memory task performance, or physiological data (e.g., heart rate, brain imaging) are integrated to provide a balanced profile.

Retrospective Analysis: Many case studies involve looking back at the participant's history through personal documents like journals or medical records to establish a baseline.

4. Key Distinctions

Feature	Case Study	Experiment
Sample Size	Usually $N=1$ or a very small group	Large groups for statistical power
Control	Low control over variables	High control over extraneous variables
Goal	In-depth description and insight	Establishing cause-and-effect
Setting	Naturalistic/Real-life context	Often artificial/Laboratory setting

Unlike experiments, case studies do not typically involve the manipulation of an Independent Variable (IV); instead, they observe naturally occurring conditions.

5. Exam Strategy & Tips

Evaluate Validity: When asked to evaluate case studies, always mention high ecological validity because they study real-life behavior in its natural context.
Address Generalizability: A common exam point is the lack of population validity; because the sample is unique, findings may not apply to the wider population ( $N=1$ problem).
Identify the Method: If a scenario describes a researcher following one person for ten years using multiple tests, identify it as a longitudinal case study.
Check for Bias: Always consider the 'researcher-participant relationship'; long-term contact can lead to a loss of objectivity, which reduces the scientific rigor of the data.

6. Common Pitfalls & Misconceptions

A common misconception is that case studies are purely qualitative; in reality, they frequently incorporate quantitative clinical data to support their findings.

Students often confuse case studies with simple observations; remember that a case study is a methodological framework that includes observations, but is not limited to them.

Another pitfall is assuming that case studies can prove causation; while they provide strong hints, the lack of controlled variables means they can only suggest correlations or provide descriptive insights.

Case Studies in Psychological Research

Summary

1. Definition & Core Concepts

2. Underlying Principles

3. Methods & Techniques

4. Key Distinctions

5. Exam Strategy & Tips

6. Common Pitfalls & Misconceptions

Case Studies in Psychological Research

Summary

1. Definition & Core Concepts

2. Underlying Principles

3. Methods & Techniques

4. Key Distinctions

5. Exam Strategy & Tips

6. Common Pitfalls & Misconceptions