Case Studies
| Unit 3: Nonexperimental Research Methods | |
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| Nonexperimental Research Methods | Unit 3 Overview | Unit 3 Outcomes | Unit 3 Resources | Correlational Research | Naturalistic Observation | Archival Research | Case Studies | Quasi-Experimental Research | Cross-sectional Research | Longitudinal Research | Survey Research | Common Threats to Internal Validity | Activities and Assessments Checklist | Practice Assignment 2 | Practice Assignment 3 |
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Case Studies
On the whole, this course emphasizes quantitative research. Quantitative researchers typically start with a focused research question or hypothesis, collect a small amount of data from each of a large number of individuals, describe the resulting data using statistical techniques, and draw general conclusions about some large population. Although this is by far the most common approach to conducting empirical research in psychology, there is an important alternative referred to as qualitative research. Qualitative research originated in the disciplines of anthropology and sociology but is now used to study many psychological topics as well. Qualitative researchers generally begin with a less focused research question, collect large amounts of relatively “unfiltered” data from a relatively small number of individuals, and describe their data using nonstatistical techniques. They are usually less concerned with drawing general conclusions about human behaviour than with understanding in detail the experience of their research participants. An important example of this approach is a case study.
A case study is the intensive, thorough examination of a single subject, or very few subjects, with a unique characteristic. The subject could be a single person or a single school, community, or event. In case studies, the observations made are generally wide‐ranging and detailed. The researcher’s original notes are often much longer and more detailed than what is later reported.
The case study approach is often used in clinical neuropsychology. For example, there is a condition called contralateral neglect, which is caused by brain damage to a region of the right hemisphere called the parietal lobe. Following a lesion to this area, people with this rare affliction develop a condition where they ignore the left side of their world. Even if the receptors in their ears and skin are functioning normally, these individuals do not respond to a noise or touch on the left side of their body (the right side of the brain controls and responds to the left side). They shave or apply makeup only to the right side of their face. If asked to draw a picture of their house, they draw only the side of the house on their right. They dress only the right side of their body. If given a meal, they eat food off only the right side of the plate. If the plate is rotated 180 degrees, they proceed to eat the remaining half. Fascinatingly, despite the odd and seemingly obvious nature of this disorder, a person with contralateral neglect is unaware that there is anything wrong.
Advantages of case studies
- Case studies allow us to study rare phenomena. Alternative approaches to studying rare phenomena, such as contralateral neglect, are often not possible. For example, for ethical reasons, it would obviously not be possible to damage the brains of people in order to produce this condition for an experiment.
- Sometimes the case study can be seen as an exploratory technique used to generate ideas and hypotheses that can then be tested experimentally.
- Case studies can challenge current theories by providing counter‐examples.
- Case studies can provide tentative support for current theories even though, by itself, the evidence the theories provide would be far from conclusive.
Limitations of case studies
- We cannot determine cause-and-effect relationships with case study methods because we cannot control all the extraneous variables (for example, an individual with contralateral neglect likely differs from most people in many ways, including the drugs the individual is taking to treat their brain damage). Therefore, there is a confounding of these variables.
- Sources of bias in interpretation of a case study are possible because the observer not only records observations but often participates in treatment as well (e.g., the observer may be the subject’s therapist). It often happens that the observer reports on subjective or unobservable behaviours (e.g., reporting what the subject thought or felt). The investigator’s primary goal and interest may be the diagnosis, treatment, and cure of a troubled patient. By serving dual roles (e.g., researcher and therapist) the objectivity of the research component may be compromised.
- There are problems with generalizing from a single case (often chosen for unique non‐generalizable traits).
- Case studies by themselves are compelling and can offer people false hope. For example, the drug Laetrile was linked in one case study to cancer remission. Although the available scientific evidence does not support its use for treating cancer or any other disease, people may have postponed or interrupted traditional therapy for cancer to pursue this unproven treatment. This limitation is valuable to remember when you hear of testimonials regarding the latest fad diet or cure for baldness.
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