Source: (2006) International Journal of Offender Therapy and Compartive Criminology. 50(1):88-100.Recent meta-analyses have documented considerable evidence demonstrating that correctional treatment programs are indeed effective for reducing recidivism in offender populations. The effect of client risk, an issue that has received extensive coverage in the extant literature from an assessment perspective, has been relatively ignored in these efforts. The present study marks the first exhaustive meta-analytic investigation of the risk principle and its effects on correctional treatment program effectiveness. The results reveal moderate support for its utility, although the magnitudes of the findings are affected by the reporting used in the practices used in the primary studies. Finally, the evidence supporting the risk principle is much stronger for female offenders and young offenders and within programs that are deemed appropriate according to the principles of need and responsibility. It should be noted the justice interventions that did not include elements of human service (e.g., increased sanctions) yielded negative results regardless of level of client risk.