Case studies are particularly useful when researchers want to get a detailed contextual view of an individual's life or of a particular phenomena.

In the social sciences they are often used to help understand the social and familial factors that might be part of the development of some form of deviant behavior in an individual.

Natural scientists might use this method to study a single animal or a single instance of some physical phenomenon.

Case studies are also useful when researchers cannot, for practical or ethical reasons, do experimental studies.