What is the primary difference between an idiographic and a nomothetic approach in research?

An idiographic approach, like a case study, focuses on the unique insights of an individual, while a nomothetic approach seeks to establish general laws and universal principles applicable to large groups.

How does a case study differ from a standard naturalistic observation?

While both occur in natural settings, a case study is much more intensive and uses multiple methods (like interviews and tests) over a long period, whereas an observation might only record behavior in a single context.

When should a researcher choose a case study over an experiment?

A case study is preferred when the phenomenon is rare, unique, or unethical to manipulate, and when the research goal is to gain rich, descriptive insight rather than establishing a cause-and-effect relationship.

Why is it problematic to generalize findings from a single case study to the general population?

Because the sample size is $n=1$ and the individual is often chosen specifically for being unusual, their behavior or biology may not represent the typical mechanisms found in the wider population.

What is the risk of a researcher becoming 'too close' to their subject in a longitudinal case study?

The researcher may lose their scientific objectivity, leading to 'researcher bias' where they interpret data in a way that supports their bond with the participant or their own preconceived theories.

What error occurs if a researcher relies solely on a participant's memories of their childhood in a case study?

This introduces retrospective bias, as human memory is reconstructive and prone to distortion, which can significantly lower the reliability and validity of the data collected.

Define 'Triangulation' in the context of case study methodology.

Triangulation is the use of multiple methods, data sources, or researchers to investigate the same phenomenon, ensuring that findings are consistent across different perspectives.

What does it mean for a study to be 'Longitudinal'?

A longitudinal study is one that takes place over an extended period of time, allowing researchers to observe how variables or individuals change and develop across different stages.

What is 'Ecological Validity' and why is it usually high in case studies?

Ecological validity refers to how well findings apply to real-world settings. It is high in case studies because they investigate individuals in their actual life contexts rather than artificial lab environments.

How can a case study of a person with brain damage help us understand the 'normal' brain?

By observing which functions are lost when a specific brain area is damaged, researchers can infer the role that area normally plays in healthy individuals, effectively using the 'exception' to prove the 'rule'.

Case Studies | AQA A-Level Psychology

Case Studies

Summary

A case study is a research method involving the intensive, longitudinal investigation of a single individual or a small group. It is characterized by its idiographic approach, focusing on unique or rare phenomena to provide rich, qualitative insights that often challenge or extend existing psychological theories.

1. Definition & Core Concepts

Case studies are defined as highly detailed, in-depth investigations of a specific unit, which is typically an individual, a small group, or an institution.
They are primarily used to explore unique or rare experiences that would be unethical or impossible to replicate in a controlled laboratory setting, such as specific neurological conditions or unusual developmental environments.
The approach is idiographic, meaning it focuses on the individual's subjective experience and unique history rather than attempting to establish general laws of behavior for a whole population.

2. Methodological Framework: Triangulation

To ensure the validity and reliability of the findings, case studies frequently employ triangulation, which involves using multiple sources of evidence to cross-verify data.
Methodological Triangulation: The researcher uses different methods, such as combining semi-structured interviews with naturalistic observations and standardized cognitive tests.
Data Triangulation: This involves gathering different types of data, such as qualitative personal accounts alongside quantitative physiological measurements or test scores.
Researcher Triangulation: Multiple researchers may observe or analyze the same case independently to reduce individual bias and increase the objectivity of the final report.

A diagram illustrating the concept of triangulation in case studies, showing the intersection of multiple methods, data types, and researchers to ensure validity.

3. Temporal Design: Longitudinal Research

Most case studies are longitudinal, meaning the participant is studied over an extended period, ranging from several weeks to many years.
This allows researchers to track developmental changes, the progression of a condition, or the long-term effectiveness of a specific intervention or treatment.
By observing changes over time, researchers can identify patterns and causal factors that might be missed in a one-off cross-sectional study.

4. Key Distinctions: Case Study vs. Experiment

5. Exam Strategy & Tips

6. Common Pitfalls & Misconceptions