Schools Chancellor Richard Carranza said Tuesday that a fatal stabbing inside a New York City school could explain an uptick in suspensions last school year — the first increase since Mayor Bill de Blasio took office.

“Last year we had an incident in one of our schools where a student was killed, and I think that that became really, really important for the system to understand that you report everything,” Carranza said in a brief interview after kicking off an implicit bias training session in Queens.

“Part of it is that people are actually now reporting everything, which I think is a good thing. That’s going to lead to a recalibration of what the baseline is,” he added.

In September 2017, Abel Cedeno, a student at the Urban Assembly School for Wildlife Conservation stabbed two of his classmates, according to police, leaving one student dead. In the months surrounding the killing, student suspensions jumped roughly 21 percent compared with the same period during the previous school year. Overall, suspensions jumped 4 percent last school year, according to city data released last week.

Carranza’s comments were his first remarks on the uptick in suspensions since the new statistics were released, and suggest that he believes educators issued more suspensions to address student misbehavior after the stabbing. (The incident was the first time a student was killed in a New York City public school in roughly two decades.)

More broadly, the de Blasio administration has encouraged schools to adopt less punitive approaches to student misbehavior by favoring “restorative” approaches such as mediation, in which school adults or peers encourage students to talk through conflicts. And the city has also made it more difficult to suspend students, requiring approval from administrators outside of the school in certain circumstances. Those changes have been controversial, with some educators arguing they have made it harder to maintain order in schools.

Carranza suggested that more reforms to school discipline policies are in the works. During a conversation Tuesday at the Queens Library with former Chancellor Dennis Walcott, Carranza specifically pointed to suspensions as an area in need of reform, noting that black students are more likely to be suspended and receive longer suspensions for the same infractions as students in other racial groups.

“If we’re satisfied with what our system produces then we’re not looking at the data,” he said.

Asked what specific policy changes might be coming, Carranza said the city is considering capping the length of suspensions, which can currently run for an entire school year, something Mayor de Blasio said last week he would discuss with his schools chief after a caller raised the idea during his weekly appearance on WNYC’s Brian Lehrer Show.

“The data that was released is jarring,” Carranza added. “It should make every single New Yorker ask the question: What is going on? We’ve actually been asking that question, we’re working on a series of things that we’re going to do to address the disproportionality.”