Author Hamish Thorburn
Published July 2018
Report Type Crime and Justice Bulletin No. 214
Subject Parole; Recidivism / Re-offending; Sentencing; Statistical methods and modelling; Evaluation reports
Keywords Reoffending, parole, parole officer, supervision, random effects

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The aim of this study was to determine the effect that parole officers have on the reoffending of parolees.


The sample chosen was all adults released on parole in NSW between 2009 and 2012. Data on parole officer, officer characteristics and office of the parolee were obtained from Corrective Services NSW. This was matched with the reoffending database (ROD) maintained by the NSW Bureau of Crime Statistics and Research to obtain demographic, index contact and prior offending variables for each parolee. The outcomes measured were reoffending within one, two or three years of release, and were recorded as binary variables. Logistic regression models were used to estimate these effects, with parole officer and parole office being included as random effects. Significance of the random effects was measured using likelihood ratio tests comparing the random effects models to the same models without the random effects included. Finally, the random parole officer effects were regressed on parole officer gender, age and years of experience to determine if these factors influenced parole officer effects.


Significant variance was found in the random effects for the parole officers for reoffending within one, two or three years, and within one and three years for parole offices. In the majority of cases, differences in parole officer and office effects accounted for less than 1 percentage point in the probability of reoffending. However, in extreme cases, this difference could be as high as 11 percentage points. No evidence suggesting that parole officer age, gender or years of experience were associated with parole officer effects was found.


It does appear that there are differences in parole officer and office effects on reoffending. However, in practical terms, these effects are very small in the majority of cases.

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