Criminal trials that are overseen by a judge alone rather than a jury have a higher likelihood of the accused person being acquitted.
A study by the NSW Bureau of Crime Statistics and Research (BOCSAR) found weaker prosecution cases might be heard without a jury, while it was also possible judges applied higher thresholds to the meaning of "beyond a reasonable doubt".
Acquittal and imprisonment rates, prison sentences and trial length for more than 5000 jury trials and 805 judge-alone trials finalised in the NSW District and Supreme courts between 2011 and 2019 were analysed as part of the research.
The proportion of judge-alone trials in NSW has jumped from six per cent in 1999 to 18 per cent in 2019.
The bureau found judge-alone trials were associated with a 12 percentage point increase in the likelihood of acquittal as well as shorter sentences for convictions.
It also found judge-alone trials that involved prejudicial and complex offences were an average of two days shorter compared to jury trials with similar cases.
Twelve legal practitioners, including judges, defence lawyers and prosecutors, were interviewed as part of the study to identify factors motivating judge-alone applications that could affect trial outcomes.
Legal practitioners believed the shortened time frame was due to the increased use of written evidence rather than in-person testimonies, flexible scheduling and quicker presentations of evidence.
BOCSAR executive director Jackie Fitzgerald said those interviewed also suggested the difference in acquittal rates could be because judges applied a higher threshold of the meaning of "beyond a reasonable doubt" compared to juries.
"Judges must also provide detailed reasons for their verdict, which can be the basis for an appeal, whereas juries do not," she said.
"Another possibility is that factors which make a case more likely to be heard judge-alone may also be associated with weaker prosecution cases."
