It examined the nature and extent of change in inmate and staff attitudes, perceptions and behavior that accompanied their transfer from the old Main Adult Facility (MAF) and the North County Detention Facility to the new Main Adult Detention Facility (MADF). Inmate and staff questionnaires included standardized questions used in prior research. The questionnaire results were supplemented by inmate criminal incident and disciplinary violation data. Findings indicate there has been a sharp decrease in the rate of more serious inmate incidents, and the overall rate of all Section 100 (criminal) disciplinary actions at the MADF has been cut in half from what it was at the MAF. The overall rate of disciplinary isolation has declined by a third at the MADF. The rate of contraband incidents actually increased at MADF, however. Inmate questionnaire data indicate that male inmates perceived greater safety, structure, privacy, support, social stimulation, freedom, and activity at MADF than they did at MAF. Male inmates showed significant improvement on three out of the four measures of stress at MADF. Results for correctional officers were mixed but generally indicated improvement. Overall, the results generally indicate that the MADF is a safer and more secure environment than MAF for both inmates and staff. 12 references and tabular data