A previous version of the headline on this article incorrectly said sexual assault reports numbered nearly 14,000. They numbered nearly 15,000. The headline has been corrected.

The Education Department found that reports of sexual assaults at elementary, middle and high schools increased sharply between 2015 and 2018, a finding advocates say underscores the need for more schools to be prepared to handle reports of sexual violence.

The finding was drawn from the Civil Rights Data Collection, a compilation of data drawn from surveys of every public school, charter school and juvenile justice facility in the nation. It was published by the department Thursday. The collection contains in-depth information about schools, including their demographics, the access students have to advanced coursework and the number of times students were arrested on school grounds. It is intended to help the department enforce civil rights law and has been a critical tool for advocates who seek to ensure schools are treating every child — regardless of race, gender or disability — fairly.

The Education Department found that reports of sexual violence at schools rose from about 9,600 in the 2015-2016 school year to nearly 15,000 in the 2017-2018 school year. That’s an increase of more than 50 percent.

“We hear all too often about innocent children being sexually assaulted by an adult at school. That should never happen. No parent should have to think twice about their child’s safety while on school grounds,” Education Secretary Betsy DeVos said in an issue brief that was published alongside the report.

The discourse around sexual assault has typically revolved around college campuses, where surveys found that up to one in five women experience sexual violence. Under President Barack Obama, the Education Department stepped up enforcement of civil rights laws that required colleges and universities to investigate claims of sexual assault.

But it has gotten far less attention in the K-12 setting, where administrators are far more likely to be unprepared or unaware of their obligations under federal law when it comes to handling allegations of sexual assault. Unlike colleges, where students often get training or information about where to go to report a sexual assault, grade school students might not know who to tell.

Shiwali Patel, director of justice for student survivors and senior counsel at the National Women’s Law Center, said the data probably represents an undercount of the sexual violence students have experienced. She has represented female students who were accused of lying and suspended from school for reporting assaults. In one case, a student who reported that she had been assaulted was pressured into recanting and then punished.

“There is so much more that needs to be done in the K-12 space to increase awareness around Title IX and sex discrimination and sexual harassment,” Patel said.

Patel said the uptick in reports could be due to better awareness around sexual assault and a movement that emboldened survivors of sexual assault to speak up. The 2017-2018 school year began just as the #MeToo movement was beginning to pick up steam — and it may have made some students more comfortable in coming forward.

The data released Thursday contained another stark finding about seclusion and restraint — practices that have historically been underreported by school districts. Seclusion is a practice that often involves segregating a disruptive student into a room or an enclosed space alone — which critics say can exacerbate whatever is driving the outburst and take them away from their education. Restraints can refer to the use of handcuffs or other equipment, or grabbing a student and holding them down.

The data showed that special education students, who represent about 13 percent of the entire school population, accounted for 80 percent of reports of seclusion and restraint.

Advocates for students with disabilities say seclusion and restraints become necessary when staff are not trained on how to de-escalate a child’s behavior.

“It’s almost the inevitable outcome in the failure to provide the supports children with disabilities need,” said Diane Smith Howard, the managing attorney for criminal and juvenile justice for the National Disability Rights Network. She said situations that end with a child being restrained often begin as something small, like a child refusing to put on shoes, and escalate from there.

A number of high-profile cases have highlighted the danger. In September of 2018, a school police officer handcuffed a boy with autism and left him on the ground for 40 minutes, according to footage that surfaced because of a lawsuit. In Michigan this year, a teenager died after being held down by staff at a residential treatment facility, resulting in criminal charges.

The pandemic could only exacerbate issues, leading to children and staff returning to classrooms with trauma wrought by the lockdown and shortages in people trained to deal with children with disabilities.

“There may be issues where school staff may be cut. Then we may end up in a situation where staff are trying to care for too many children and end up using seclusion and restraint,” Smith Howard said. “There’s just a lot of pieces there that could result in children having greater needs.”