Understanding variations in murder clearance rates: The influence of the political environment

A crucial challenge facing police administrators, especially in times of heightened political and public attention, is the pressure to make appropriate organizational and procedural changes to improve homicide investigation performance, measured by an increase in murder clearance rates. Murder clearance rates are politically salient, inviting the charge that the police manipulate the numbers so that the mayor looks good at the next election. The purpose of this study is to analyze the impact of the political environment on murder clearance rates. The research strategy employed a multi-method research design, using both quantitative and qualitative approaches. The quantitative research design is based on data organized using a pooled cross-section time-series analysis of 59 of the largest cities in the United States over the period 1970 to 1999. The model estimates the impact of the mayoral election year, murder offense rate, police expenditures, number of employees, population, and state unemployment rate on murder clearance rates. The model was analyzed using cross-sectional time-series feasible generalized least squares regression. The estimate for the critical mayoral election variable was re-estimated to test for simultaneity, omitted variables, and different functional forms. The results consistently reveal no discernible political impact of the mayoral election year on murder clearance rates. The results also imply that the addition of sworn officers improves the murder clearance rate, but simply adding more resources (e.g., patrol cars, equipment, training, personnel, etc.) does not. The qualitative design was conducted in one large city. It examined department documents, along with extensive field observations and interviews. The case study demonstrated that the media, mayor, city council and prosecuting attorney exercised a significant impact on police practices and procedures, investigative decision-making and even fluctuations in homicide case closures. Continued review of the political environment's influence on police practices and procedures will provide more evidence as to its actual impact. This dissertation identifies the need to develop, implement and evaluate an investigative performance model that includes more functional performance measures for all homicide investigation activities and improved accountability for the use of resources.