In some states, seventeen-year-old youths are automatically prosecuted as adults. In other states, certain offenses automatically require adult prosecution, and some states give prosecutors and the courts discretion to try youths as adults. Thirty-one states have “once an adult, always an adult” policies, which mandate that if someone under eighteen has ever been charged as an adult, all of their future cases must also be handled in the adult system.

Thirty years ago, there were 2,300 kids held in adult jails. From 1990 to 1999, youth jail populations increased by 311%, peaking at 9,458. That number then began to decline, culminating in a 2016 population of 3,700, still far more than the already-high 1990 number.

Thirty years ago, there were 2,300 kids held adult jails. From 1990 to 1999, youth jail populations increased by 311%. The data for prisons, available from 2000 forward, follows a pattern of consistent decrease. 3,892 kids were confined in adult prisons in 2000; by 2016 this number had fallen to 956 — still far too high.

The decline in number of youths in adult facilities represents a more general decline in the number of youths coming into contact with the criminal justice system. Between 2005 and 2014, the number of youths arrested dropped by 51.2%; similarly, between 1997 and 2013, the number confined in correctional facilities dropped by 48%. Some of the decline in youth incarceration, however, is the result of youths aging out of the statistics but remaining behind bars for crimes committed before they were eighteen.

Much of the general decline in youth confinement in adult facilities is the result of legal and legislative changes brought about by youth-focused criminal justice advocacy. In 2005, the Supreme Court ruled in Roper v. Simmons that imposing the death penalty for a crime committed while the offender was under eighteen violates the Constitution. In doing so, the court established the principle that children cannot be held to the same standards of responsibility as adults, nor can their actions be considered evidence of an “irretrievably depraved character.” This decision established the legal precedent for rollbacks of mandatory life sentences for juveniles and other policies that kept youth imprisoned.

States have also been taking independent legislative action, including raising the age of juvenile jurisdiction. Since juvenile courts are more likely to hand down sentences other than confinement, these laws reduce the number of people under eighteen who end up in jail or prison. State legislatures have also focused on delinquency prevention efforts, creating intervention programs for at risk-youth and diversion programs for nonviolent offenders.

While these legislative decisions are steps in the right direction, they still leave thousands of children in adult facilities, condemning them to countless long-term harms.

Incarcerating youth in adult facilities is even more harmful than incarcerating them with people their own age. Of all incarcerated people, youth held with adults are at the highest risk of sexual abuse; they are also 36 times more likely to commit suicide than youth in juvenile facilities, and are at a greater risk of being held in solitary confinement than they would be in juvenile facilities.

Read the full article about incarcerating youth with adults by Maddy Troilo at Prison Policy Initiative.