Following your previous suggestions, I have tried to read more about articles using meta-analytic techniques. And I found that the seminal meta-analysis of the correctional treatment literature indicated that offenders who participated in therapeutic activities had an approximate 10% lower rate of recidivism compared with those offenders who did not participate in treatment. That is very impressive!!! However, I am still very confused about how to apply it to our program design and evaluation…

Not at all.

Thanks a lot.

Yes. Understanding the theoretical mechanisms by which criminal conduct occurs and knowing the relative importance of certain risk factors for such behavior is important, but it is equally important to understand whether criminal behavior is modifiable and, if so, what methods may best achieve change among correctional clients. Compelling research has accumulated over the years that indicate correctional rehabilitation programs produce positive outcomes, particularly in reducing recidivism. For instance, reductions in recidivism were enhanced in treatment contexts in which the guiding model of Risk, Need, and Responsivity was followed. That is, rehabilitation efforts can be optimized when (a) the intensity of services is titrated to the criminal potential of the client (Risk)—higher risk clients receive more intensive services; (b) rehabilitation services attend to the key criminogenic characteristics of the client (Need), with criminogenic characteristics being those related to crime; and (c) services are delivered that are attuned to clients’ learning styles/abilities (Responsivity)—such that the opportunities for learning and behavior change are greatest. Indeed, the meta-analysis demonstrated that “appropriate” services (i.e., broadly adhering to RNR) were associated with a 30% reduction in future criminal behavior. Further research on this model (D. A. Andrews & Bonta, 2010; D. A. Andrews & Dowden, 2005) has found a strong proportional link between adherence to the RNR principles and reductions in recidivism—the greater the adherence to the principles, the greater reductions in recidivism.

You could find more information below:
Andrews, D. A., & Bonta, J. (2010). The psychology of criminal conduct (5th ed.). New Providence, NJ: LexisNexis.
Andrews, D. A., & Dowden, C. (2005). Managing correctional treatment for reduced recidivism: A meta-analytic review of program integrity. Legal and Criminological Psychology, 10, 173-187.