Although crime prevention is not a specific task of the PEP model, project designers envisioned that crime reduction would result from the PEP approach. Research was conducted to evaluate the impact of two PEP's on housing service delivery, crime, and community life over a 3-year period. The two PEP's had high crime rates and adverse design and social characteristics. Basic elements of PEP's housing service model (local estate offices, repairs, and caretaking) were implemented on both estates. At the end of the research period, resident feelings about the PEP were mixed. The PEP brought a greater sense of security and a real increase in some residents' feelings of safety from racially motivated victimization. Nonetheless, other residents had become poorer, more socially heterogenous, and more apathetic. Changes in environmental design, tenant consultation, and population characteristics created different vacancy levels on the estates. Financial circumstances of estate newcomers worsened, while stable and established tenants displayed more confidence about the estates and the possibility of improvements. Crime decreased on the PEP estates, but some intraneighbor tensions remained. Territoriality, social cohesion, and empowerment increased among some residents due to environmental modifications and PEP's efforts to involve them in service improvement and estate management. Even so, some newly arrived single-parent families were especially vulnerable to crime. Two obstacles to the wider effectiveness of the PEP model on the two estates were identified: (1) quality of implementation; and (2) instability of residential communities due to population turnover, social heterogeneity, and the "subterranean culture" within estate communities. Further information on the impact of PEP and supplementary tables are appended. 86 references, 24 tables, and 3 figures