There are several potential mechanisms whereby education have its effects:

A Pathway to Prosocial Job Opportunities

For some, educational opportunities offered to those impacted by the justice system can open doors to legitimate employment opportunities. Earning a high school diploma or GED is the bare minimum acceptable degree for even low-skill jobs. In the case of learning a trade (e.g., flooring, roofing, HVAC, plumbing), it's an opportunity to learn a marketable skill that they can use to make significant money over time.

An Investment in Prosocial Society

Just the act of having participated in educational opportunities offered to justice involved individuals takes time and energy. This time and energy is an opportunity cost that is lost if they recidivate or continue to exhibit antisocial behavior in the workplace. It's entirely possible that they perceive this time and energy as wasted if they don't pursue a legitimate opportunity afforded by the training.

An Opportunity to Practice Prosocial Skills

We use a higher proportion of prosocial skills throughout the day than many of those involved in the justice system. We use problem solving and other communication skills to resolve conflicts. There are many justice involved individuals who use a higher proportion of antisocial skills to solve their problems every day. Just like how we can immediately start riding a bike after years without practice, we can use prosocial skills without thinking about it. That's not true of those who rely on antisocial skills to solve problems. Like any skill, it requires practice, which participation in the classroom provides. They have to reliably complete homework, deal with frustration, interact with classmates, and communicate their questions/concerns effectively as they navigate the educational environment. It's possible that some of the impact of education is actually the opportunity to practice prosocial skills that it provides for those who need it.

Although it is probable that the way the education is delivered (e.g., type of program, learning styles attended to, demographics targeted) has an effect, it is important to understand the mechanism we're interested in. This is likely to help us better understand the variance in recidivism rates as it relates to education. I've just scratched the surface on each of these mechanisms, and I'm sure there are several others I didn't include here. Regardless, if you're interested in exploring how different educational opportunities impact recidivism, these are some things to explore as you approach the study.