Prediction of recidivism

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Research summary
Vol. 1 No. 1
May 1996


Is the Statistical Information on Recidivism (SIR) scale still a valid measure of offender risk?


The Statistical Information on Recidivism (SIR) scale is an objective risk assessment instrument originally developed in the Ministry of the Solicitor General and subsequently adopted by the Correctional Service of Canada (CSC) as part of their risk assessment process. The original research that produced the SIR used a sample of federal inmates released between 1970 and 1972. There has been some concern that the SIR scale may no longer retain its predictive power given the changes in the offender profile over the intervening years. The present study evaluated the predictive power of the instrument on a more recent sample of federal inmates.


The revalidation study was conducted on a sample of 3,267 male inmates released from penitentiaries in 1983/84. SIR scores were calculated for this sample and the offenders were followed for three years after release. RCMP criminal history records were used to measure recidivism.


The major finding was that scores on the SIR scale were related to future recidivism. The study also investigated the prediction of violent recidivism with the SIR. The earlier research could not adequately investigate the validity of the SIR scale with violent recidivism because of the infrequency of violent re-offending. In this new study, SIR scores were found to predict violent recidivism, although not with the same power as general recidivism.

The researchers conducted a statistical analysis (Receiver Operating Characteristic) that allowed for an evaluation of the present categories of risk defined by the SIR and a comparison of the SIR to other risk scales. The SIR defines five risk groupings (Poor to Very Good) depending upon SIR scores.

The analysis confirmed the present categorization of risk used by CSC. In addition, the predictive accuracy of the SIR was compared to the Statistical Risk Assessment Guide (SRAG), an instrument that includes the Psychopathy Checklist developed by Robert Hare. With respect to general recidivism, the SIR performed as well as the SRAG. The SIR did not predict violent recidivism as well as the SRAG, but the differences were marginal.

Policy implications

  1. The results from the research re-affirm CSC's use of the SIR as one measure of an offender's general risk for recidivism and supports the present categorization of risk.
  2. The results also support National Parole Board's policy of using the SIR to assist in release decisions.
  3. The SIR compares favourably to another validated risk scale, the SRAG. Although the SRAG performed better than the SIR in the prediction of violent recidivism, the small amount of improvement must be weighed against the additional costs of using the SRAG.
  4. The SIR performed reasonably in the prediction of violent recidivism. Using the SIR for the prediction of violent recidivism is still cautioned and continued research on the prediction of violent offending is required.


For further information

James Bonta, Ph.D.
Solicitor General Canada
340 Laurier Avenue West
Ottawa, Ontario
K1A 0P8
Tel (613) 991-2831
Fax (613) 990-8295

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