The effect of judge-alone trials on criminal justice outcomes

By Jonathan Gu

AIM To estimate the association between judge-alone trials and the probability of acquittal, trial length, and sentence severity. METHOD We compared 5,064 jury and 805 judge-alone criminal trials finalised in the NSW District Court and Supreme Court between January 2011 and December 2019, excluding cases where the defendant entered a guilty plea to their principal offence or had a special verdict of “not guilty by reason of mental illness” (under s. 25 of the Mental Health (Forensic Provisions) Act 1990 (NSW)). Entropy balancing was used to match judge-alone cases with jury cases on available covariates. We then estimated the association between trial type (judge-alone vs jury) and four criminal justice outcomes, adjusting for relevant observable factors. The analysis was repeated for two subsets of offences: violent offences and offences with a higher likelihood of having prejudicial elements or complex evidence (prejudicial and complex offences). We also interviewed 12 legal practitioners, including District and Supreme Court judges, prosecutors, and defence lawyers, to identify factors motivating judge-alone applications that may be correlated with the outcomes of interest. RESULTS We estimated that compared to jury trials, judge-alone trials are associated on average with a statistically significant nine percentage point increase in the probability of acquittal and a shorter prison sentence by 7.6 months. Within prejudicial and complex offences, we found that judge-alone trials were associated with a statistically significant decrease in average trial days. Judge-alone trials were also associated with a statistically significant decrease in prison sentence length for the violent offences subgroup. Interviewees suggested that increased use of written submissions may influence both shorter trial length in judgealone matters and reduced prison sentences (i.e., via discounts from efficiencies resulting from pre-trial cooperation or time saved by submitting tendered evidence). Interviewees stated that judge-alone applications in NSW are mostly made in cases with prejudicial elements (e.g., evidence that cannot be separated from prior proven offending) or complex evidence (e.g., cases with substantial scientific or financial evidence). CONCLUSION Judge-alone trials are associated with an increased probability of acquittal, shorter trials, and a shorter prison sentence. However, we cannot determine whether these differences are driven by confounding factors (such as strength of the prosecution’s case) and/or causal factors.

Sydney: NSW Bureau of Crime Statistics and Research, 2024. 49p.