Gritz, R. M., and Johnson, T. (2001). National Job Corps Study: Assessing program effects on earnings for students achieving key program milestones. Report Prepared for the U.S. Department of Labor, Employment and Training Administration.
- The study’s objective was to estimate the impact of Job Corps on the employment and earnings of participants who obtained a general education development (GED) certificate or vocational training certificate during the course of the program. Job Corps offers intensive academic classroom instruction and vocational skills training to economically disadvantaged youth.
- Job Corps’ overall effectiveness was evaluated using a randomized controlled trial—the National Job Corps Study (NJCS)—conducted in 48 states and the District of Columbia (see the Clearinghouse for Labor Evaluation and Research [CLEAR] profile of Schochet et al. 20011 for full results). For this report, the authors used data from the NJCS 48-month follow-up survey to match Job Corps participants to control group members who had similar propensities to obtain a GED or vocational certificate.
- The study found that Jobs Corps participants who completed a vocational certificate during the course of the program earned $40 to $50 per week more than their control group counterparts, and those who completed a GED earned $60 to $70 per week more.
- The quality of causal evidence presented in this study is moderate, the highest possible rating for a nonexperimental study. This means that we have some confidence that the estimated impacts are attributable to achieving programmatic milestones in the Job Corps program, although other factors might also have contributed.
Features of the Intervention
Job Corps is a federally funded program that has been in operation since 1964. It offers individualized academic education, vocational training, counseling, and job placement assistance to economically disadvantaged youth ages 16 to 24. Services are delivered at Job Corps centers, where most Job Corps students reside while participating in the program. Most participants do not have a GED or high school diploma upon program entry and they participate in the program for an average of eight months.
Features of the Study
The NJCS was a randomized controlled trial conducted at 119 Job Corps centers in 48 states and the District of Columbia. Eligible youth were randomly selected either to receive an offer to participate in Job Corps immediately or to not be able to participate in Job Corps until three years later (the control group). The study team administered a follow-up survey to both groups approximately 48 months after random assignment to collect data on the outcomes of interest. The sample included about 11,000 youth in total.
Although the official Job Corps study offers the definitive estimates of the average impacts of the program for all participants, this study employs a nonexperimental design to estimate the impact of the program specifically for those participants who earned a high school diploma, GED certificate, or vocational training certificate during the program (approximately 39 percent of the total program group).
The authors employed two nonexperimental approaches to isolate the impacts of Job Corps for those who completed an educational credential during the program. In the first approach, the authors used statistical methods to match Job Corps participants to control group members who had similar likelihoods of completing an educational credential. They then compared the earnings of the matched Job Corps and control group members. In the second approach, the authors tried to isolate the true impact of Job Corps after controlling for individual differences in the likelihood of attaining a credential.
- The NJCS reported average earnings impacts of $20 to $25 per week across all those who had been randomly assigned to be offered admission to the Job Corps program. The current study found that almost all of these earnings impacts accrued to Job Corps participants who had completed an educational credential during the program.
- Jobs Corps participants who completed a vocational certificate during the course of the program earned $40 to $50 per week more than their control group counterparts; those who completed a GED earned $60 to $70 per week more.
Considerations for Interpreting the Findings
The authors used two nonexperimental methods in this report. The first approach used propensity-score modeling to match Job Corps participants to control group members who had similar likelihoods of completing an educational credential. The groups were well-matched, so this analysis provides moderate causal evidence, the highest rating possible for a nonexperimental design.
The second method involved trying to isolate the true impact of Job Corps after controlling for individual differences between those who completed programmatic milestones and those who did not. However, as noted by the authors, this method did not adequately control for differences between these groups, so it provides low causal evidence.
Causal Evidence Rating
The quality of causal evidence provided by the propensity-score matching portion of this study is moderate. This means that we have some confidence that the estimated impacts are attributable to achieving programmatic milestones in the Job Corps program, although other factors might also have contributed.