A sociological method analogous to medical case-histories, tracing the career of a phenomenon through one example or many, which enables comparative and longitudinal analysis. The extended history of a selected case may be one of a number in a case-study research project, providing an enormously detailed and substantiated account, with reference to some specific characteristic or experience. The most common type is the life-history of an individual which, despite its title, is necessarily selective, giving a post hoc account of the antecedents, causes, consequences, contextual factors, perceptions, and attitudes associated with some key feature of the person or their experience—such as the fact of their being an immigrant, criminal, or charismatic leader. By their nature, such case-histories give greater emphasis to personal characteristics than to structural factors, and to specific processes rather than general patterns. Case-histories sometimes take as their unit of study a group, organization, or community, and are thus closely allied to the case-study. A single case-history is often used to generate hypotheses for further study. Case-histories are also used extensively in psychiatry and social work, and in criminology and clinical psychology, employing the skills and methods of the respective disciplines.