Examining the Relationship between Crime Rates and Clearance Rates Using Dual Trajectory Analysis
Advisor: Cynthia Lum, PhD, Department of Criminology, Law and Society
Committee Members: Christopher Koper, Sue-Ming Yang, Daniel Nagin
Research Hall, #301
July 01, 2016, 10:00 AM to 07:00 AM
Police agencies dedicate large amounts of resources, and place a great deal of importance, on criminal investigations and solving crimes. However, very stable clearance rates over time in the U.S., coupled with highly fluctuating crime rates begs the question of whether there is actually a relationship between these efforts and crime rates. Specifically, if police improve their ability to solve crimes, does this have any effect on crime rates over time? A deterrence relationship might indicate that an increase in clearance rates leads to a decrease in crime rates. However, while some prior research indicates evidence of a deterrent effect when examining the relationship between crime rates and clearance rates, other research using various methods has found that crime and clearance rates move in the same direction, or have found no clear relationship between crime and clearance rates.
This dissertation further explores the longitudinal relationship between crime clearance and crime rates using an innovative method known as dual trajectory analysis. Examining all police agencies with 100 or more sworn officers in the United States, dual trajectory modeling is carried out on clearance rates and crime rates for the offenses of homicide, robbery, aggravated assault, and burglary from 1981 – 2013. Findings show that while there are discernible longitudinal patterns of both clearance and crime rates, no clear relationship between crime rates and clearance rates emerges from the dual trajectory analysis for this sample (although some interesting findings are noted). Implications for understanding the relationship between crime and clearance rates are discussed, as well as ideas for future research.