A leading sociological theory of crime is the "routine activities" approach (Cohen and Felson, 1979). The premise of this theory is that the rate of occurrence of crime is affected by the convergence in time and space of three elements: motivated offenders, suitable targets, and the absence of guardianship against crime. The purpose of this study was to provide empirical evidence for the routine activities theory by investigating criminal data on places. This study deviates from traditional criminology research by analyzing places instead of collectivities as units of spatial analysis. There are two phases to this study. The purpose of the first phase was to test whether crime occurs randomly in space or is concentrated in "hot spots". Telephone calls for police service made in 1985 and 1986 to the Minneapolis Police Department were analyzed for patterns and concentration of repeat calls and were statistically tested for randomness. For the second phase of the study, two field experiments were designed to test the effectiveness of a proactive police strategy called Repeat Complaint Address Policing (RECAP). Samples of residential and commercial addresses that generated the most concentrated and most frequent repeat calls were divided into groups of experimental and control addresses, resulting in matched pairs. The experimental addresses were then subjected to a more focused proactive policing. The purposes of the RECAP experimentation were to test the effectiveness of proactive police strategy, as measured through the reduction in the incidence of calls to the police and, in so doing, to provide empirical evidence on the routine activities theory. Variables in this collection include the number of calls for police service in both 1986 and 1987 to the control addresses for each experimental pair, the number of calls for police service in both 1986 and 1987 to the experimental addresses for each experimental pair, numerical differences between calls in 1987 and 1986 for both the control addresses and experimental addresses in each experimental pair, percentage difference between calls in 1987 and 1986 for both the control addresses and the experimental addresses in each experimental pair, and a variable that indicates whether the experimental pair was used in the experimental analysis. The unit of observation for the first phase of the study is the recorded telephone call to the Minneapolis Police Department for police service and assistance. The unit of analysis for the second phase is the matched pair of control and experimental addresses for both the residential and commercial address samples of the RECAP experiments.