The effect of GPS refresh rate on measuring police patrol in micro-places

Oliver K Hutt,Kate Bowers,Shane D Johnson

doi:10.1186/s40163-021-00140-1

Abstract

With the increasing prevalence of police interventions implemented in micro hot-spots of crime, the accuracy with which officer foot patrols can be measured is increasingly important for the robust evaluation of such strategies. However, it is currently unknown how the accuracy of GPS traces impact upon our understanding of where officers are at a given time and how this varies for different GPS refresh rates. Most existing studies that use GPS data fail to acknowledge this. This study uses GPS data from police officer radios and ground truth data to estimate how accurate GPS data are for different GPS refresh rates. The similarity of the assumed paths are quantitatively evaluated and the analysis shows that different refresh rates lead to diverging estimations of where officers have patrolled. These results have significant implications for the measurement of police patrols in micro-places and evaluations of micro-place based interventions.

Highlights

Police patrols are often targeted at areas of above-average risk of crime occurring—areas known as crime hot-spots
This study found that police patrols had a significant impact upon crime and disorder, with patrols lasting up to around 15 min and on average lasting around 8 min
The intention of this paper was to explore the potential impact of measurement error in the use of Global Positioning System (GPS) data to measure police foot-patrol

Summary

Introduction

Police patrols are often targeted at areas of above-average risk of crime occurring—areas known as crime hot-spots. The second experiment was conducted with the Metropolitan Police Service (MPS) London and used a faster than standard ping refresh rate in order to measure how different refresh rates impacted on the assumed paths which officers took (and would influence the estimate police patrol time in crime hot-spots).

Results

Conclusion