There’s this phrase you hear in the news sometimes: the school-to-prison pipeline. It’s shorthand for how schools are funneling students — especially black students — into the criminal justice system. It started in the 90s, when schools responded to fears about crime with zero tolerance policies, which mandated suspensions and expulsions for certain violations. They also cracked down on little things like talking back or uniform violations. But as a result, out-of-school suspensions have doubled since the 1970s, and keep increasing even though juvenile crime rates have now been dropping for years. Around the same time, the number of police officers stationed full-time inside schools has increased — by a third between 1997 and 2007. Ostensibly, they were there to prevent mass school shootings like the one at Columbine. But they end up being a way for schools to basically outsource discipline to the police. Schools with officers have five times as many arrests for "disorderly conduct" as schools without them. Sometimes the results are shocking. But the less visible effect is that schools are feeding the racial disparities in the criminal justice system. Consider the fact that schools are more likely to have an officer on their campus if their student population is more than 50% black. You might assume that’s because there’s more crime at these schools. But although students at policed schools are more likely to be arrested, they’re not actually more likely to be charged in court for weapons, drugs, alcohol, or assault, at least according to one study. During the 2010-2011 school year, one in six public school students in the U.S. were black, but they accounted for one in three arrests at school. Same goes for other forms of school discipline. Black students are suspended or expelled three times more frequently than white students. It actually begins in preschool. 18% of preschoolers are black, but of all preschoolers suspended more than once, 48% are black. Studies show that differences in behavior can’t fully account for these disparities. Black students and white students are sent to the principal's office at similar rates, but black students are more likely to end up with a serious punishment. One study found that white students are more likely to be suspended for provable offenses like smoking or vandalism, while black students are more likely to be suspended for subjective reasons like talking back or insubordination. Students who are suspended in school are more likely to later drop out or get arrested, so the federal government is asking schools to make suspension and expulsion the absolute last resort. In Oakland, California, public schools are trying something called restorative justice, where both parties to a conflict talk it out with a counselor, instead of relying on punishment. The results are pretty encouraging— in the past ten years, chronic absenteeism is down and graduation rate are up in the schools that have tried it. Other cities and districts are also trying new policies — so that if their students end up in the criminal justice system, it won’t be because the schools pushed them there.