The most satisfactory basis for deciding how to allocate Psychological Service treatment resources lies in a combination of offence and reconviction base rates, seriousness of offence, and treatment effectiveness.

The Psychological Service Prediction Rating Scale accurately predicts probability of reconviction. Directing psychological treatment to offenders with high probabilities of reconviction will contribute most to the department's aim to reduce re-offending. At any time, there are likely to be as many such offenders serving community-based sentences as in prison.

The strategy of directing resources to high-risk offenders must be modified by consideration of the seriousness of some offences. Some offenders with low probabilities of reconviction commit very serious crimes if they do re-offend, and this should be taken into account when allocating treatment resources. It is the basis for allocating treatment resources to special units. Reconviction prediction must be improved by discovering psychological variables which will allow middle probability offenders to be re-classified as low or high probabilities. Efforts must be made to find psychological variables to identify people with low probabilities of reconviction, but most likely to commit serious crimes if they do re-offend.

Psychological treatment based on cognitive-behavioural principles, and with a high level of integrity, effectively reduces reconvictions. It is as effective for those in prison as it is for those serving community-based sentences. It might be more efficient to deliver treatment to prisons, given their higher levels of consent and adherence to treatment, and better opportunities to establish and maintain group therapy. Better data and more sophisticated analyses are required, however, before reaching a firm decision.

Despite the effectiveness of treatment, it also fails. Developmental work must: identify psychological variables associated with re-offending; improve existing or develop new ways to assess them; improve existing or develop new treatments to modify them. Young offenders pose a particular challenge — they may require a more comprehensive treatment strategy than currently provided.