(NewsNation) — The effectiveness of school resource officers (SROs) is unclear as some school districts opt to remove the police presence from their campuses.

At least 49 school districts, serving about two million students from 2020 to 2021, have either cut budgets to school policing programs or ended them all together, according to Education Weekly.

Last week, a student was stabbed and killed after a fight broke out at a school in Santa Rosa, California. The school has not had SROs since 2020.

“It’s really important to understand that the Santa Rosa Police Department did not remove the SROs from the school campus. So I think that’s very important. That’s a decision by the Santa Rosa school board,” said Santa Rosa police chief John Cregan.

Many school districts made this decision in the summer of 2020 as police departments across the country came under intense scrutiny.

Mo Canady, executive director of the National Association of School Resource Officers, told NewsNation he believes SROs are important in preventing violence at schools.

The National Association of School Resource Officers is a non-profit that provides training across the country.

“When you don’t have those protectors there it’s certainly one less barrier that violence has to go through. It’s removing a protective factor against violence,” said Canady. “SROs are not only the last line of defense in a critical situation, they’re most likely the first line of defense.”

However, not everyone agrees. Some argue violence in schools needs to be addressed holistically, without the use of SROs.

“We simply ever so often, always resort to SROs or resort to kind of blaming young people for the violence that happens within the school when honestly a young person just needs someone to talk to,” said youth organizer Meyiya Coleman.

“A lot of young people expressed that they felt like they were in prison, I felt like I was in a prison, going through metal detectors, seeing armed officers in my school,” Coleman said.

The National Education Association says research shows SROs do little to reduce on-campus violence, and that their presence disproportionately harms students of color and those with disabilities.

The National Association of School Resource Officers strongly disagree, saying their officers help prevent student injuries and reduce the need for schools to call 9-1-1.

Some have reported that the pandemic and lockdowns escalated bad student behavior

“There has certainly been higher aggression, I’ve mostly seen it with our young boys,” said Dee Hanbury, a school social worker serving a school in the Bronx in New York. “We should be trained, and teachers need to be trained, and deans need to be trained, and anyone who works with students needs to be trained to see behaviors.”

Still, some school districts that chose to get rid of their SROs now want them back.

A deadly school stabbing in St. Paul, Minnesota, prompted the district to bring back some police officers as parents raised concerns about increasing rates of violence.

In Denver, Colorado, some students are asking for schools to bring back SROs out of fear for their safety.

“We have had way too many instances where I feel sros could have been a help in our building and they just weren’t there,” said Denver high school student Alaijah Sims.

A 2015 study looking at police strategies and management said the effectiveness of SROs and other security personnel is mixed. They did appear to be effective in mitigating and confronting problems like bullying and gangs on high school campuses.