| ||Literature Coverage Dates||Number of Studies||Number of Study Participants|
|Meta-Analysis 1||1979 - 1997||13||0|
|Meta-Analysis 2||1990 - 1999||3||2132|
|Meta-Analysis 3||1980 - 2011||22||0|
Wilson, Gallagher, and MacKenzie (2000) examined the effectiveness of corrections-based education, vocation, and work programs for adult offenders through a meta-analysis of 33 experimental and quasi-experimental evaluations. Studies were included in the meta-analysis if they 1) evaluated an education, vocational, or work program for convicted adults or persons identified by the criminal justice system, 2) provided a postprogram measure of recidivism (including arrest, conviction, self-report, technical violation, or incarceration), 3) included a nonprogram comparison group (a comparison group that did not receive an educational, vocational, or work program), 4) were published after 1975 in English.
A thorough search of the literature led to the inclusion of 33 eligible studies. The program comparison–contrast was the unit of analysis, allowing for multiple program comparison–contrasts for each study. The 33 studies reported 53 program comparison–contrasts that were identified and coded for the analysis. More than 40 percent of the studies (14 out of 33) were from journal articles or book chapters. The other studies were either government documents (10 out of 33) or unpublished manuscripts (9 out of 33). The studies generally had large sample sizes. The median number of participants across the program groups was 129, and the median number across the comparison groups was 320 (a total number of participants was not provided). Slightly fewer than half of the studies included only male participants. Female participants were included in 19 studies; however, they generally represented fewer than 21 percent of the study sample, therefore it is difficult to generalize findings from the analysis to women. In the remainder of the studies, it was unclear whether study participants included both men and women. Information on the age and racial/ethnic breakdown of the study samples was not provided.
There were 13 studies (out of 33) that examined the relative effects of postsecondary education. The form of effect size selected was the odds ratio. Recidivism was the primary outcome of interest. This was measured as a dichotomy (i.e., the percentage or proportion of program and comparison participants who recidivated).Meta-Analysis 2
Chappell (2004) conducted a meta-analysis of studies examining the effects of postsecondary correctional education (PSCE) on recidivism. Only published articles and unpublished research finalized between 1990 and 1999 were included in the review. PSCE was defined as any type of education beyond high school, or its equivalency, that has inmates in prisons or jails for students (including vocational, academic, undergraduate, graduate, certificate, or degree programs). If studies combined data on inmates participating in PSCE with inmates receiving adult basic education and GED courses, they were eliminated. Studies had to include recidivism rates of program participants to be included. Studies were located through literature reviews and requests of information from the Correctional Education Association. The review included correlational and quasi-experimental studies.
Fifteen studies were included, with a total sample size of 7,320 subjects. However, because the 15 studies included research designs without control groups, a smaller meta-analysis was conducted specifically with the studies that had control groups. In this smaller meta-analysis, there were only three studies with control groups, for a total sample size of 2,132 subjects. No information was provided on the age, gender, or racial/ethnic breakdown of the studies’ samples, nor on the location of the programs.
The effect size was calculated as the sample-weighted mean r,
so that studies with larger sample sizes were given more weight than those based on smaller samples.Meta-Analysis 3
Davis and colleagues (2013) conducted a meta-analysis of evaluations examining the effectiveness of programs that provide education to incarcerated adults. A comprehensive literature search was done that covered the period from Jan. 1, 1980, through Dec. 31, 2011. To be included in the review, a study needed to 1) evaluate an eligible intervention, 2) measure success of the program using an eligible outcome measure, and 3) employ an eligible research design. Eligible interventions were defined as educational programs administered in jails or prisons in the United States and published (or released) during the time covered by the review. In this review, postsecondary education was defined as college-level instruction that enables an individual to earn college credit that may be applied toward a 2- or 4-year postsecondary degree. Eligible outcomes were defined as measures of recidivism (including reoffending, rearrest, reconviction, reincarceration, technical parole violation, and successful completion of parole), employment (including having ever worked part time or full time since release, having been employed for a specified number of weeks since release, and employment status), and achievement test scores. Eligible research designs were those in which there is a treatment group composed of inmates who participated in or completed the correctional education program under consideration and a comparison group composed of inmates who did not.
The search resulted in the inclusion of 58 eligible studies. Of the 58 studies, 22 looked at the effectiveness of postsecondary education programs on recidivism rates. There were not enough studies looking at the effects of postsecondary education on employment and achievement test scores to calculate an effect size. No information was provided on the age, gender, or racial/ethnic breakdown of the studies’ samples. The programs were located at correctional facilities throughout the United States.
The meta-analysis used a random-effects approach. The form of effect size selected was the odds ratio. The quality of each study was rated using the University of Maryland’s five-point scale; only studies that received a rating of 2 or higher on the scale were included in the analysis (a rating of 2 means a study used a quasi-experimental design but there were substantial baseline differences between the treatment and comparison groups that may not be controlled for well). The U.S. Department of Education’s What Works Clearinghouse (WWC) rating scheme was also used, because the WWC instrument scores education studies; however, the Maryland Scale was primarily used to determine the rigor of studies.