Comparing Measures of the Concentration of Crime at Places

The primary objectives of this research are (1) to introduce summary measures of concentration that are relatively new to our field; (2) compare four concentration measures to determine whether there are reasons to use one in favor of the others; and (3) apply the measures to a real-case data to further understand the concentration phenomenon. Using the crime data of Cincinnati, we compare four commonly used social science measures of concentration: Gini, Simpson, Shannon, and Decile indices. For some purposes, the measures are interchangeable, while for other purposes the measures may suggest different interpretations for the same set of data. This paper is the first quantitative comparison of multiple measures of crime place concentration. We describe the benefits and limitations of each index and the circumstances for which each is most useful. We also answer the question: is crime within street segments spread along the segment or is it concentrated at a few addresses, as most place-based crime studies have overlooked the interior variability of crime on street segments