ASTUDENT MISBEHAVES and gets sent to the principal and then home. It’s a scenario that gets played out in countless classrooms every day; so commonplace is the practice that it’s generally seen as no big deal. But as a new report on school discipline in Virginia makes clear, the effects of lost school time can be devastating and — contrary to conventional thinking — do little to improve student behavior or make schools safer.

A study released this month by the JustChildren Program of the Legal Aid Justice Center found that more than 90,500 students were suspended or expelled from a Virginia school in 2010-2011, many of them more than once. The rate of suspensions and expulsions amounted to 884 per day. Most disciplinary incidents were for minor misbehavior that did not involve weapons, drugs or injury. The top four causes, according to the group’s research, were defiance, classroom/campus disruption, making obscene/inappropriate language or gestures and disrespect.

“We can fill over 4,500 classrooms with the students who were suspended at least once last year,” said Angela Ciolfi, one of the report’s authors. Disproportionately affected are students from economically disadvantaged backgrounds, students with emotional and behavioral disabilities and minority students (particularly black males). What results from high suspension rates are low student achievement, more dropouts and increased contact with the juvenile justice system. That’s a high price to pay, considering that this punishment has little effect in changing student behavior or in maintaining a positive school climate.

What’s particularly distressing about the Virginia numbers is that, while there is a proven alternative, few school districts have adopted it. The Effective Schoolwide Discipline program gives individualized support to students who struggle; Virginia schools that have used it show lower referrals for discipline, decreased suspension and expulsion rates and savings in administrative and instructional time. Only 12 percent of the state’s schools use it.

To its credit, the Virginia Board of Education has tried to encourage districts to switch to the system, offering incentives and providing training, but it generally treats discipline as a local issue. This report should spur the board to exert even more leadership in this critical area.