The first set of studies consisted of investigations of defensible space hypotheses based on architectural and crime data from over 100 public housing developments in New York City. Archival crime data from the New York City Housing Authority, data from the New York police, and tenant and building characteristics data were used to investigate the relationship between physical variables, crime rates, and the locations of crimes within the buildings. The second study focused on a comparison of the Van Dyke and Brownsville public housing projects in New York City on the basis of physical characteristics, tenant attitudes, and crime rates. Data were collected through site visits, tenant interviews, and the study of archival records of the New York City Housing Authority. The third study consisted of a random survey of 425 tenants in 7 public housing projects in New York City. Overall, only limited statistically reliable conclusions can be drawn from the studies regarding the ability of architectural design to create defensible space and to reduce crime and fear of crime. This is because no adequate operational definitions of defensible space are provided. Although building height appears to have a significant effect on robbery rate, as does the variable percent of population receiving welfare, much further refinement is needed before defensible space can be used as an empirically based concept.