In the criminal justice world, there’s an ongoing debate about whether to increase the age of majority, the point at which an adolescent can no longer be tried in the juvenile legal system and instead must be tried as an adult.

Advocates of raising this threshold say it’s unfair to process juveniles in the adult system because their brains are not fully mature. They lack the emotional bandwidth to make good decisions. Upping the age of majority, the argument goes, lessens the chance they will reoffend because they will have access to rehabilitative opportunities in the juvenile justice system. Critics of the idea say it may lead to increased recidivism among adolescents.  

According to new research from University of Pennsylvania criminology professor Charles Loeffler and colleagues, both groups may be wrong. “For misdemeanor crimes, whether you process a juvenile as a juvenile or as an adult, it’s unlikely to reduce or increase reoffending,” he says.

Loeffler, the Jerry Lee Assistant Professor of Criminology, and Ben Grunwald, a Fellow at the University of Chicago Law School who earned his doctorate from Penn, published their results in The Journal of Legal Studies, using data from the Chicago Police Department.

On Jan. 1, 2010, Illinois raised its age of majority for misdemeanors from 17 to 18. Before the law took effect, a 17-year-old arrested for this type of crime was processed as an adult; just after, this same teenager went through the juvenile system, which, among other benefits, doesn’t result in a permanent record.

“It’s literally the chance of how your birth date interacts with the specific date you get arrested that determines whether you move through the juvenile system or the adult system,” Loeffler says. “It makes for a very clean comparison, especially when you compare this before-and-after difference for 17-year-olds to 16- and 18-year-olds unaffected by the law.”

That’s what Loeffler and Grunwald did for nearly 23,000 young adults, looking at how many 16- to 18-year-olds arrested prior to and following the law change committed additional crimes during the next two years.

“The reoffending rates for juveniles prosecuted in both of these systems are nearly indistinguishable and actually quite high,” Loeffler says. “Unsurprisingly, people don’t seem to do too well in either legal system.”

The implications of this research vary by state. Those concerned about the fairness of processing juveniles as adults can consider raising the age of majority without fear of negative consequences for public safety. States primarily interested in reducing juvenile recidivism should look elsewhere for answers.

Loeffler says alternative recidivism reduction approaches do exist. One is cognitive behavioral therapy (developed at Penn in the 1960s by psychiatrist Aaron Beck), which gives people tools to navigate difficult social and emotional situations.

Another is called “swift, certain and fair sanctions,” which substitutes quick, predetermined, less-severe punishments for long-delayed and sometimes harsh punishments. A system using swift, certain and fair sanctions will always punish a crime, even with a light sentence.

“Preliminary results have shown that when you have a system more aligned with [this method], you can dramatically reduce reoffending rates among targeted populations,” Loeffler says. “That’s in contrast with our results about shifting the age of majority.”

He acknowledges some limitations to his study, including the fact that the information came from a single city. He says he would also like to see research on how raising the age of majority affects other factors such as a person’s employment and health, as well as exactly how each of these two judicial systems responds to adolescent offenders.

For now, the age of majority discussion endures. “There’s been a big push in the past five years. That’s why you’ve seen all of these different states” — Massachusetts, Connecticut, Illinois, New Hampshire — “make the move” to raise this threshold, he says. “Fewer and fewer states today have sub-18 ages of majority. It’s an active conversation.”