The importation model focuses on inmates' roles and values before incarceration, whereas the deprivation model focuses on inmates' responses to problems of adjustment posed by institutional deprivations and the conditions of confinement. The treatment models used in juvenile institutions can be grouped into four categories depending on whether custody or treatment is the main organizational goal and whether the interventions are oriented toward the group or the individual. The four institutions in Massachusetts used for the present study each reflect one of these four categories. Data were collected in each of the 10 cottages by a team of 5 trained researchers who spent about 6 weeks in each unit administering questionnaires and interview schedules to both staff members and residents. The study matched and controlled for the effects of differences in inmates' background characteristics between settings. Results demonstrated a clear and consistent relationship between the formal and informal organizations. The more custodial and punitive settings had inmate cultures that were more violent, more hostile, and more oppositional than those in the treatment-oriented settings. The crucial organizational differences lay in the extent to which staff members contained and controlled subterranean inmate violence by encouraging the communication of information about the activities within the inmate subculture. Tables and footnotes are provided. (Author abstract modified)