The block groups used in this study were sampled as part of a National Institute of Justice funded study examining informal social control in high drug use neighborhoods. Consequently, the sampling plan for the block groups was developed to assure a sufficient number of high drug use neighborhoods, as well as an adequate distribution of predominantly White, predominantly Black, and predominantly racially mixed neighborhoods. To achieve these goals census block groups were first placed into one of three strata: high drug use, adjacent to high drug use, and nonadjacent to high drug use. Using data from a previous study that interviewed crack and injection