Police Arrests and Correctional Workload

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Release date: 4 July 2011

Every time police arrests rise by 10 per cent, Government expenditure on male prisoners increases by $18.7 million per annum, while Government expenditure on female prisoners goes up by $2.2 million per annum.

Ninety per cent of full-time prisoners in NSW are male; 10 per cent are female.

Increases in arrest rates also have a big impact on the cost of supervising offenders in the community. Every 10 per cent increase in arrests results in an additional $2.6 million per annum being spent supervising male and female offenders in the community.

These results emerge from the first Australian study into the relationship between police arrests and correctional workload. The study was conducted by the NSW Bureau of Crime Statistics and Research.

The Bureau studied the relationship between police arrests and (a) the number of male and female offenders sentenced to full-time prison terms (FTPs) and (b) the number of offenders given community-based supervised orders (SOs). The study covered the 153 months from January 1998 to September 2010.

The Bureau's research shows that a 10 per cent increase in police arrests results in a 2.3 per cent increase in the number of SOs one month later. If the 10 per cent change becomes permanent, the increase in SOs is estimated to be 4.1 per cent in the long term.

A 10 per cent increase in the number of male arrests produces an immediate (same month) 3.3 per cent increase in the number of male FTPs. If the 10 per cent change becomes permanent, the increase in male FTPs over the long term is estimated to be 4.0 per cent.

A 10 per cent increase in female arrests produces a 4.6 per cent increase in female FTPs one month later.

The short-run costs of a 10 per cent increase in police arrests are spread over 11 months for supervised orders and male full-time imprisonment and over 8 months for female full-time imprisonment.

Commenting on the findings, the Director of the Bureau, Dr Don Weatherburn said that "changes in arrest rates obviously have significant and rapid impacts on demand for correctional services."

"The lesson from this research is that Governments need to make adequate provision for the downstream impact of policies likely to result in an increased arrest rate."

Further enquiries: Dr Don Weatherburn 02-9231-9190