 The case study approach is a useful tool for investigating complex issues in their real-world contexts. It has been widely used in business, law, and policy, but its application in health services research is less common. This paper discusses the various types of case study designs, the questions they can help answer, the data sources typically employed, and the advantages and disadvantages of using this methodology. Additionally, it provides guidance for designing and evaluating case study proposals, as well as a checklist for assessing the quality of case study reports. This article was authored by Hubby Guro, Robertson Ann, Cresswell Catherine, and others.