Author Hamish Thorburn and Don Weatherburn
Published January 2018
Report Type Affiliated publication
Subject Aboriginal / Indigenous Australians; Assault; Sentencing
Keywords Disparity, generalized estimating equations, imprisonment, prison, Aboriginal offenders, sentencing, serious assault

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Recent studies have found evidence of a racial bias in sentencing in Australia despite previous work showing the opposite. However, in some cases, these studies fail to adjust properly for differences in offence seriousness and in others fail to control for important covariates. Our aim in this study was to investigate the relationship between Indigenous status and likelihood of imprisonment for serious assault offences, matching on offence seriousness and controlling for additional covariates. Multivariate logistic regression with generalized estimating equations was used to explore the effect of Indigenous status on the likelihood of a prison sentence while controlling for the other sentence-relevant factors. Interaction effects were examined by fitting a logistic regression model with all covariates separately for Indigenous and non-Indigenous offenders and comparing the coefficient of each covariate for differences. The results show that the marginal increase in the risk of a prison sentence for Indigenous offenders is less than one percentage point (3.40% for Indigenous offenders compared with 2.45% for non-Indigenous). Significant interaction effects between Indigenous status and whether or not the offence was domestic violence related (p = .024), whether or not the offence was committed after 2011 (p = .020) and whether or not the offender had previously been issue a community service order for a serious assault offence (p = .025) were found, each of which altered the probability of imprisonment. Despite this, no interaction effect was found that resulted in a difference in marginal probability of imprisonment greater than 1.2 percentage points between Indigenous and non-Indigenous offenders. We conclude that while there is a significant effect of Indigenous status on sentencing, the effect is vastly reduced when controlling for additional covariates.