Do Crime Hot Spots Move? Exploring the Effects of the Modifiable Areal Unit Problem and Modifiable Temporal Unit Problem on Crime Hot Spot Stability

• NCJ Number: 250376
• Author(s): Joel M. Hunt
• Date Published: 2016
• Length: 274 pages
• Publication Format: Dissertation/Thesis
• Publication Type: Research Paper; Research (Applied/Empirical)
• Language: English
• Country: United States of America
• Note: Full text available from NCJRS. Submitted to the Faculty of the School of Public Affairs of American University in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Justice, Law, and Criminology.

Annotation

The aim of this research was to explore the apparent contradiction between academicians and practitioners with respect to the stability of crime hot spots.

Abstract

This research explored the apparent contradiction between academicians and practitioners with respect to the stability of crime hot spots. Calls-for-service data from Arlington, TX, and Charlotte-Mecklenburg, NC, for the years 2005-2010 were used to test the effects of grid cell size and period duration length on the effectiveness, efficiency, and measured hot spot stability of the random walk model. This research employed the Prediction Accuracy Index (PAI) for measuring the effectiveness of the random walk method; this research also introduced and employed the Prediction Efficiency Index (PEI) for measurement of efficiency of the random walk method. To measure the hot spot stability of the random walk method, the percentage of grid cells classified as a hot spot in two adjacent time intervals was used. Results indicated the general relationship that the PAI value decreases with increasing grid cell size. Charlotte-Mecklenburg showed a general positive relationship between grid cell size and PEI, whereas no such general relationship was found for Arlington. As the period duration was increased, no general finding was observed with regard to its effect on the PAI. Conversely, a negative relationship was found in both cities with respect to the effects of period duration on PEI. Four findings emerged: (1) as period duration increased, the percentage of stable hot spots increased; (2) different crime types were found to have different hot spot stabilities; (3) the hot spot break point technique affected the percentage of stable hot spots relative to the number of hot spots that the break point classified; and (4) grid cell size did not affect the measured stability in a similar manner across the two cities. While not generalizable to all jurisdictions, this research provides a framework for police departments to conduct similar analyses to provide a transparent, effective, and efficient means of defining place and time with regard to crime hot spots. (Author abstract modified)