Diurnal Movements and the Ambient Population: An Application to Municipal-Level Crime Rate Calculations

Abstract

Crime rates are often used to inform the public regarding their risk of criminal victimization. However, these crime rates are themselves at risk of misinforming the public. Recent research has used alternative crime rate calculations to show that these calculations are quite sensitive to the choice of population at risk, but this research has been undertaken only at the neighbourhood level, not at the municipal level. In this paper, municipal-level crime rates are calculated using conventional and alternative means to show the sensitivity of the crime rate. It is shown that because of our diurnal movements throughout metropolitan areas, municipalities gain and lose significant populations. And because of these changing populations, municipal-level crime rates must be calculated, and interpreted, with caution.