“Comprehensive, accurate, and reliable data are needed to guide the development of innovative juvenile justice policy. NJP provides empirical evidence that communities can use to develop and provide appropriate services within detention centers. Because the study is longitudinal, it also provides information about the long-term outcomes of these youth after they leave detention. Findings from NJP [Northwestern Juvenile Project] … provide important information on how to facilitate successful reentry into the community and successful transition to adulthood for youth in the juvenile justice system” (p. 3). Sections of this overview of NJP include: highlights; background; differences between NJP and other longitudinal studies of psychiatric disorder among detained youth; NJP’s overall approach and goals; sampling and interview methods; considerations for measurement; key areas of measurement; overview of selected findings for characteristics of youth in detention and key outcomes of study participants; and summary.