Unlike traditional research methods, case studies allow you to take an in-depth look at a specific program or group of people to understand specific elements related to IPM adoption and behavior change. For case studies, the subjects (samples) are not random, but are logically selected based on the research questions being addressed. For example, you could be examining if and how several farmers are using a new IPM method promoted by your program, or you might be studying how apartment residents deal with pests. In any case, your sample will be small and selective.
Seek Potentially Information Rich Cases
Most importantly: Refer to your evaluation objective(s) or questions to guide your sample selection. Subjects are chosen on the basis of providing information that will help you answer these questions. For example, if your goal is to understand factors that contribute to a successful wheat IPM program, it would be useful to identify both successful and less successful farming operations, to understand their information sources, farming and pest management practices and to examine their economic outcomes. It would be less informative to examine an “average” program. This kind of purposeful sampling is critical to building a successful case study. Look for potentially information rich cases, including both successful and non-successful programs, IPM adopters and non-adopters, etc. to gain the most information out of the time invested.