Determining how journeys-to-crime vary: Measuring inter- and intra-offender crime trip distributions

Abstract

Journey to crime studies have attempted to illuminate aspects of offender decision making that has implications for theory and practice. This article argues that our current understanding of journey to crime is incomplete. It improves our understanding by resolving a fundamental unit of analysis issue that had thus far not received much attention in the literature. It is demonstrated that the aggregate distribution of crime trips (commonly known as the distance decay) does not take into account the considerable variation that exists between individual offenders' crime trip distributions. Moreover, the common assumption of statistical independence between observations that make up a distribution is something that, until now, has yet to be tested for distributions of crime trips of multiple offenders. In order to explore these issues, three years of burglary data from a UK police force were linked to 32 prolific offenders to generate journey to crime distributions at the aggregate and offender levels. Using multi-level models, it was demonstrated that the bulk (65%) of the variation of journeys to crime exists at the offender level, indicating that individual crime trips are not statistically independent. In addition the distance decay pattern found at the aggregate level was not, in the main, observed at the offender level - a result that runs counter to conventional wisdom, and another example of the ecological fallacy. The implications of these findings are discussed. © 2009 Springer New York.