Sentencing consistency in the New Zealand District Courts

Abstract

This thesis examines the consistency of sentencing between the circuits of the New Zealand District Courts. Four predictions based on a sequence or chain of theories incorporating the concept of bounded rationality from decision making theory, the influence of formal and substantive rationalities on sentencing decisions, court community theory, and personal construct psychology were tested. The circuit in which sentencing took place was expected to affect the likelihood of incarceration and to affect the length of incarceration. If these predictions were met, it was further predicted that the weight applied to some or all of the sentencing factors would vary between circuits. It is understood to be the first study controlling for a wide range of sentencing factors examining the consistency of sentencing between locations in New Zealand and one of the first from anywhere outside of the United States. The four predictions were tested using sentencing data from the two years 2008-2009 for three high volume offences (aggravated drink driving, male assaults female and burglary). Sentencing was treated as a two part decision process, with the selection of a sentence type followed by the determination of the sentence amount. Each prediction was separately modelled for each offence. Different types of model were chosen as being more suitable for the specific predictions: logistic regression for the likelihood of incarceration; linear regression for the length of incarceration; multi-level generalised linear regression with random co-efficients to determine if the weight applied to specific factors varied by circuit in the determination of whether or not to incarcerate; and multi-level linear regression with random co-efficients to determine if the weight applied to specific factors varied by circuit in the determination of sentence length. The logistic regression and linear regression models demonstrated that there were statistically significant and substantively significant differences between circuits in the likelihood and length of incarceration. The extent of inconsistency varied by offence type with the most marked differences occurring for aggravated drink driving and burglary. Offence seriousness and criminal history factors were found to be the principal influences on both sentence decisions for all three offences. The multi-level models for aggravated drink driving and burglary revealed a core of seriousness and criminal history factors whose influence varied across the circuits. The models for male assaults female were less informative, highlighting the likelihood that these models were limited by the omission of key sentencing variables and the narrow scope of this particular assault type within the wider spectrum of assaults. The findings should not be interpreted as if they are a critique of the sentence imposed in any individual case or of the sentencing by any judge or in any circuit. It is a critique of sentencing guidance in New Zealand and its ability to achieve a fundamental tenet of justice: the similar treatment of similar offenders being sentenced in similar circumstances. In addition to testing the predictions the multi-level models were extended to address whether the observed variation in sentencing was associated with variations in circuit context. Due to the limited number of circuits (17) and multi-collinearity between the contextual variables, bivariate analyses had to be employed. The modelling revealed a consistent difference between provincial and metropolitan circuits; the two categories of circuit were distinguished from one another by many of the other more specific variables that had a significant association with sentencing approaches. The provincial circuits were more likely to incarcerate and to impose longer sentences. However, the small number of circuits and multi-collinearity between the variables precluded more detailed analysis to identify which of the contextual variables distinguishing metropolitan and provincial circuits had the greatest influence. These findings have significant implications for the judiciary and for sentencing policy makers. Urgent attention should be given to addressing opportunities to increase the availability of sentencing guidance to reduce the degree of inconsistency. More detailed offence based sentencing guidance is required; in the current context there are two options that could be used. The Court of Appeal could issue a broader range of guideline judgments or the legislation for the Sentencing Council and the process for developing and promulgating guidelines could be implemented. For logistical and public policy reasons the Sentencing Council approach is preferred. There is a risk that failure to address the levels of inconsistency will result in the sentencing system falling into disrepute.