4.7 Risk of Re-offending

All sentenced inmates are assessed in terms of their risk of re-conviction and re-imprisonment, using a statistical indicator known as “RoC*RoI” (Risk of re-Conviction/Risk of re-Imprisonment). Risk assessment is used by the Department to ensure that rehabilitative services are directed at those most likely to re-offend.

The risk score assigned to an individual is a decimal between 0.0 and 0.99. A score of 0.5 suggests that the individual has a 50 percent probability of being re-imprisoned within five years (alternatively, if 100 individual offenders with this score were followed up over five years, approximately 50 would be expected to be re-imprisoned within this time).

Key variables used in determining an individual’s risk rating include the offender’s current age, age at first conviction, number and seriousness of convictions, and time elapsed between convictions. Research conducted by the Department confirms RoC*RoI as an accurate measure of an individual’s probability of further offending(1) .

The table below indicates the percentage of sentenced inmates in each decile band. The male census population tended towards higher risk levels, something commonly found when inmates are compared to non-imprisoned offenders (i.e., those serving community sentences). Census females tended to display lower-risk scores than males, consistent with the finding of considerably lower recidivism rates amongst female offenders generally.

Table 4-7 Risk scores of sentenced inmates

Risk Groups	Female		Male		Total
Risk Groups	Number	Percent	Number	Percent	Number	Percent
Less than 0.1	42	16.0%	285	5.9%	327	6.4%
0.1 – 0.19	25	9.5%	239	4.9%	264	5.2%
0.2 – 0.29	25	9.5%	231	4.8%	256	5.0%
0.3 – 0.39	30	11.5%	257	5.3%	287	5.6%
0.4 – 0.49	27	10.3%	304	6.3%	331	6.5%
0.5 – 0.59	23	8.8%	392	8.1%	415	8.1%
0.6 – 0.69	17	6.5%	472	9.8%	489	9.6%
0.7 – 0.79	14	5.3%	571	11.8%	585	11.5%
0.8 – 0.89	13	5.0%	603	12.5%	616	12.1%
0.9 – 0.99	1	0.4%	268	5.5%	269	5.3%
No score available	45	17.2%	1211	25.1%	1256	24.7%
Total	262	100.0%	4833	100.0%	5095	100.0%

Percentages may not add to 100 because of rounding.

1 L Bakker, D Riley, J O’Malley, Risk of Reconviction, 1999, Department of Corrections, Wellington.