The effects of prison sentences and intermediate sanctions on recidivism

General Effects and Individual Differences 2002-01 The views expressed are those of the authors and are not necessarily those of the Portfolio of the Solicitor General of Canada. [...] Thus, the purpose of this meta-analysis was to update the results that we have previously reported regarding the three general classes of sanctions and to examine these results as they pertain to the aforementioned offender groups. [...] Next, the obtained correlations were transformed into a weighted φ value (z+) that takes into account the sample size of each effect size and the number of effect sizes per type of sanction (Hedges & Olkin, 1985). [...] Assessment of the magnitude of the effect of various sanctions on recidivism was conducted by examining the mean values of φ and z+, as well as their respective 95% confidence intervals (CI). [...] The CI is a range of values about the mean effect size that, a specified percentage of the time (i.e., 95%), includes the respective population parameter.