When to Use a case Study

Using Multiple Strategies

• More than one strategy can be used in a study.
• Which comes first, the survey or the case study?
• [Sam D. Sieber. “The Integration of Fieldwork and Survey Methods”. The American Journal of Sociology, Vol. 78, No. 6, (May, 1973), pp. 1335-1359. http://www.jstor.org/stable/2776390]

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DEFINING THE SAMPLE

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MULTIPLE CASES NEEDED WHEN

• Bracketing. What is happening at the extremes? What explains differences?
• Best cases/Worst cases. Why is (isn’t) it working?
• Cluster. How do different types of instances compare with each other?
• Representative. How do different types of instances chosen to represent important variations compare and why?

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Multiple Case Studies

• Same study contains more than a single case.
• For example, Study of school innovations. Independent innovations occur at different sites.
• Every case should have a specific purpose.
• Often needed for explanatory case studies. Replication - same results predicted for each case or contrasting results for predictable reasons.

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SINGLE CASE APPROPRIATE

• Exploratory. In this particular circumstance, what is happening and why? Could be an extreme or unique case.
• Typical. In a typical site, what is happening and why?
• Critical instance. Does this single instance support the theory?

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Embedded Case Studies

• Within a single case (single public program), the analysis includes outcomes from individual projects within the program.
• Embedded units selected through sampling or cluster techniques. (Project characteristics)
• More frequent versus holistic approach.

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