They included children who idled at home for a day or two and some who accompanied their parents to work.

They included the pre-kindergarten son of Rajuawn Thompkins, who said the boy was removed from his D.C. charter school for kicking off his shoes and crying in frustration. Thompkins had thought the boy was too young to be suspended.

He was 4.

“I would explain it to him, and he still didn’t understand,” she said. “He’d ask me, ‘Mommy, why can’t I go to school?’ ”

His pointed question underlies a debate about the merits of out-of-school suspension.

Some researchers and critics question whether children in the early grades should ever be suspended. The goal should be teaching appropriate behavior, they say, not sending students home.

Still, many educators see suspension as necessary — a strong message about conduct that crosses the line. Many parents, too, suggest that students who cause a disruption in class, no matter what age, need to be removed. Especially when a child or teacher has been physically hurt, many principals view suspension as an important tool.

A Washington Post analysis of data for 13 of the region’s school systems found that last school year more than 6,112 elementary students, from pre-kindergarten through grade 5, were suspended or expelled for hitting, disrupting, disrespecting, fighting and other offenses.

The total includes 433 kindergartners, 677 first-graders, 813 second-graders and 1,086 third-graders. More than 50 pre-kindergartners were suspended.

In all, those cases represent a small segment of suspensions in the region, and affect from 1 percent to 3 percent of elementary children in most school systems. But some experts say that age sets them apart.

For children younger than 7 or 8, “all they understand a couple of days into this is they are having snow days — and nobody else is,” said Walter S. Gilliam, author of a national study on pre-kindergarten expulsions and director of the Edward Zigler Center in Child Development and Social Policy at the Yale Child Study Center.

Gilliam said suspension is at odds with teaching the social and behavioral skills many young students lack. “We would never send a child home because that child was struggling at reading,” he said. “We would never send a child home if that child was struggling with math. Why would we send a child home for struggling with social-emotional skills?”

On those removed from school, the effect is complex. They lose instruction time and slip behind in classes. But there may be other fallout, too: lower regard from peers or teachers, a shift in identity, an alienation from school. “I would be worried it would set in motion a negative trajectory that would gather momentum across the next years of schooling,” said Anne Gregory, a Rutgers University assistant professor and education researcher.