When to Use a Case Study Approach So when should you use a case study approach? According to Yin (2003) a case study design should be considered when: (a) the focus of the study is to answer “how” and “why” questions; (b) you cannot manipulate the behaviour of those involved in the study; (c) you want to cover contextual conditions because you believe they are relevant to the phenomenon under study; or (d) the boundaries are not clear between the phenomenon and context. For instance, a study of the decision making of nursing students conducted by Baxter (2006) sought to determine the types of decisions made by nursing students and the factors that influenced the decision making. A case study was chosen because the case was the decision making of nursing students, but the case could not be considered without the context, the School of Nursing, and more specifically the clinical and classroom settings. It was in these settings that the decision making skills were developed and utilized. It would have been impossible for this author to have a true picture of nursing student decision making without considering the context within which it occurred.