Longitudinal Research in the Social Sciences

•Longitudinal research concerns the collection and analysis of data over time. Longitudinal data are essential if the research purpose is to measure social change: they allow a diacronic analysis of the incidence of conditions and events. •Several types of data may be regarded as longitudinal: repeated cross-sectional studies; prospective studies, retrospective studies. Because longitudinal research is a broad term, methods for the analysis of social change may also vary substantially. •Longitudinal research can potentially provide fuller information about individual behaviour; however, the use of such data poses crucial theoretical and methodological problems.