Author Evarn J. Ooi
Published March 2019
Report Type Crime and Justice Bulletin No. 222
Subject Alcohol; Drugs and Drug Courts; Evaluation reports
Keywords Fixed-effects, Longitudinal, Alcohol, Drug, Rehabilitation, Infractions, Staggered treatment

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This study investigates the impact of participating in the Intensive Drug and Alcohol Treatment Program (IDATP) on prisoner misconduct.


To estimate the effect of IDATP on prisoner misconduct, the main identification strategy exploits the natural variation in the timing of the program start date among every male participant since the program began in 2012. We use the years in gaol before IDATP as the comparison among the participants only, via a fixed-effects specification. By using participants as their own comparison, the empirical strategy avoids the selection bias issues that arise when using non-participants as the control group. The outcome of interest is prisoner misconduct, which is captured by the annual number of infractions of prison rules committed by each IDATP participant during their gaol sentence.


The main results indicate that prison infractions committed in gaol decreased by approximately 73 per cent in the years after participation in IDATP, among male participants. Additional findings from a supplementary analysis support the main result. Specifically, we do not observe a reduction in infractions after a cohort of male prisoners were due to receive IDATP, but were ultimately denied treatment for plausibly exogenous reasons.


Overall, the findings indicate that participating in IDATP has a beneficial influence on prisoner misconduct.

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