Developing a Crime Harm Index for Western Australia: the WACHI

Abstract

Research Question Can a reliable measure of precise harm levels for the 100 most harmful and frequently occurring offences be developed in Western Australia (WA) based on analysis of actual court penalties for first-time offenders? Data Criminal and traffic court sentences in 2.2 million records over 6.5 years were analysed to extract the number of days of imprisonment actually imposed in sentencing decisions for approximately 52,000 first-time offenders (see House 2017). Methods Sentences for all first offenders in a sample of the 102 most common offence categories were analysed to compute for the median number of days of imprisonment to which each first offender was sentenced in each of the categories. Monetary penalties and conditional community sentences were converted to equivalent 'prison days' and added to the computation of the median of days of imprisonment per offence category. The number of reported offences in WA in the study period for each of the 102 categories was then multiplied by the median prison days sentenced per category. The sum of the products of median prison days times offence count was then tallied across all offence categories to form a weighted index of crime harm, which we define as the Western Australian Crime Harm Index (WACHI). Applying a minimum requirement of at least five separate court cases for each crime category, a total of 88 offence categories survived the reliability threshold for inclusion in the index. Findings The 88 offence categories in the WACHI contain both high-harm and highvolume offences, permitting 95% of all offences reported for over 5 years to be assessed for WACHI scores. The counts for these offences moved in different directions from the WACHI total in two of the four year-to-year comparisons. Changes in WACHI were shown to have been highly sensitive to increased reporting of historical sex crimes, isolated in one district each of both Metropolitan Perth and one Regional centre.Camb J Evid Based Polic (2018)

Designing the Swedish Crime Harm Index: an Evidence-Based Strategy

“…Therefore, creating a CHI based on penalty scales, maximum, average or minimum, would be unsatisfactory. Notably, in Australia, researchers considered using the maximum sentences but rejected the method because of insufficient variability (Kwan 2016;House and Neyroud 2018).…”

“…All of these are based on the average length of the sentences for the different crimes. A variation of this method was used by House and Neyroud (2018), who developed a Crime Harm Index for Western Australia, which is based on the average length of sentence for a first-time offender, and Curtis-Ham and Walton (2017), who developed a New Zealand Crime Harm Index, based on estimates of the minimum sentence for a first-time offender using sentencing data.…”

“…Meanwhile, House and Neyroud (2018) rejected the use of penal code metrics in Western Australia because they provided insufficient sensitivity to the differences across perceived normative severity of various offence types.…”

“…There is no Swedish dataset that can distinguish first-time offender, as was available to House and Neyroud (2018), or the minimum sentence for a first-time offender (Curtis-Ham and Walton 2017). Focusing on first-time offender gives an equivalent valuation for each crime, merely based on harm, without adjustment for the offender's criminal history or other circumstances of a particular offence, but this is not possible using the available Swedish sentencing data.…”

Redrawing Hot Spots of Crime in Dallas, Texas

“…The Western Australia Crime Harm Index was developed by House & Neyroud (2018) to analyze harm levels among common offenses for first-time offenders. It was calculated by taking the median number of days sentenced for each first time offender in a sample of most common offense categories.…”