The “Power Curve” of Victim Harm: Targeting the Distribution of Crime Harm Index Values Across All Victims and Repeat Victims over 1 Year

Abstract

Is the vast majority of crime harm in one police force area over 1 year suffered by a small percent of all known victims, with many of those most-harmed victims suffering repeated and perhaps preventable crimes if more police resources were to be invested in them? All 30,244 crimes recorded as committed against all 25,831 persons with one or more known victimization reported between 1 June 2015 and 31 May 2016 in Dorset, UK. Each criminal event was weighted by the Cambridge Crime Harm Index (CHI) method, using the number of days of imprisonment recommended by the Sentencing Council for England and Wales as the “starting point” for sentencing offenders convicted in each crime category. Regardless of whether an offender was detected or convicted, each crime was coded with the starting point penalty. The total number of days assigned was then summed across all crimes in Dorset and individually for each victim, with the victims rank-ordered from highest to lowest number of total days of recommended imprisonment assigned to each (the Cambridge CHI value). Under 4% of victims (968) suffered 85% of the CHI value of total days of recommended punishment for the crimes against all victims, with sex offences and robbery contributing almost two thirds of total CHI harm (63%).Almost one third (29%) of the harm were committed against repeat victims, including their first victimization within the 1-year period. Slightly over half of the harm against those repeat victims (57% of the harm across 4211 victimizations against repeat victims) occurred after their first victimization, equal to 15% of total harm to all victims that year. Just 256 repeat victims, comprising 1% of all victims, suffered 26% of total victim harm, ranging from 2 to 14 victimizations per person. The mean CHI value for each of these repeat victims was 1396 days (∼4 years) of recommended imprisonment for the totals of anywhere from 2 to 14 crimes against each member of this beleaguered 1%. The overall concentration of harm in a tiny fraction of all victims forms a “disproportionality ratio” of 15:1, with the “power few” most-harmed 4% of victims suffering 15 times more harm than expected if all victims suffered equal harm, with the highest disproportionality ratios of any offence types, 19 to 1 for sex offences and 5 to 1 for robbery. Conversely, the total CHI value of thefts was 0.143:1 or only one seventh of what it would have been with an equal distribution of harm across all criminal events. The ratio for burglary was 0.25:1, and even for violence (0.67:1), there was 33% less harm than expected for equal harm by crime type. The vast majority of crime harm in one UK police force area over 1 year was suffered by a small percent of all known victims, with 15% of total harm occurring as repeat victimizations. This finding demonstrates the value of better algorithms for predicting repeat victimizations to allocate prevention resources, starting with the Cambridge CHI value of each first offence against each victim.