The findings indicate that the majority of Lisbon's police precincts are efficient in handling security and preventing crime; however, a small number of inefficient precincts need to upgrade their operational efficiency in order to meet the standards of best practice. The efficient precincts, on the other hand, must continually monitor their efficiency in order to ensure that it is maintained. Socioeconomic variables linked to crime causes, notably poverty, were a negative influence on the precincts' efficiency. Efforts to increase precinct efficiency, therefore, must involve a comprehensive, coordinated effort by multiple city agencies in eliminating slums, integrating immigrants into the economic mainstream, and decreasing the unemployment rate. DEA (data envelopment analysis) was used to analyze precinct efficiency. Farrell (1957), Charnes, Cooper, and Rhodes (1978) used the term DEA to describe the mathematical programming approach to the construction of production frontiers. DEA also measures the efficiency of the constructed frontiers. DEA is applied to unit assessment of homogeneous units such as police precincts. The unit of assessment is usually referred to as a decisionmaking unit (DMU). A DMU converts inputs into outputs. The current study estimated the production frontier by using panel data on 33 Lisbon police precincts for the years 2000, 2001, and 2002. The second stage estimated a Tobit model in which the efficiency scores were regressed with socioeconomic variables related to crime causes (immigrant population, unemployment, and slums). 6 tables, 57 references, and appended DEA model used in the study