Prison population forecasting is fraught with difficulty. Many factors affect the size of the prison population, including levels of crime, the number of arrests, the proportion of arrestees convicted, the proportion refused bail, the proportion given a prison sentence, the average length of prison sentences, the proportion of offenders released to parole at the end of their non-parole period and the rate at which parole is revoked.
This report provides short and long-term forecasts of the number of prisoners in NSW. Three long-term forecasts are provided; one of which assumes no further growth in age-specific rates of imprisonment, and another two of which assume a continuation of the growth that has occurred either over the last ten years or over the history of available data (32 years), respectively. In order to provide some context for the forecasts we begin by describing long-term trends in the remand and sentenced prisoner numbers and some of the factors that have influenced growth in these populations.
The short-term forecast is that, if relevant influences remain unchanged, NSW will have 12,191 prisoners by March 2017. If age-specific rates of imprisonment remain constant, we expect the NSW prison population to rise to 12,500 by June 2036. If age-specific rates of imprisonment rise in a manner commensurate with trends observed over the past decade, the prison population should reach 15,600 by June 2036. If age-specific imprisonment rates rise according to the trends observed since 1982, the prison population should reach 17,600 by June 2036.
The NSW prison population is likely to rise over both the short and long-term unless measures are taken to reduce the demand for prison accommodation.