According the the Department of Education, there were 69,643 suspensions last school year, an overall decline of 5.2 percent from the year before. The number of longer-term suspensions in New York City schools, lasting more than five days, declined by nearly 12 percent last school year over the year before. The average length of those suspensions, known as superintendent suspensions, was about 20 days, education officials said.

In 2011-2012, black students, who represent 28 percent of the student population, served more than half of suspensions citywide. Special education students served 32.3 percent of total suspensions, though they represent 12 percent of the student body.

“Under the Bloomberg administration we have seen two phenomena that work together to undermine the environment in the schools and drive kids out,” said Donna Lieberman, director of the New York Civil Liberties Union. “One is the zero-tolerance discipline where there was a mandate of suspension for a far greater range of offenses, including a lot of very subjectively defined offenses,” such as what constitutes “harmful” or “disruptive” behavior under the discipline code.

Lieberman said she thinks that an increased police presence in schools has also contributed to an environment of suspensions, with more arrests or summonses, rather than the use of more positive interventions.

“Students should not fear going to school and being targeted by the Department of Education and the New York Police Department,” Cheyanne Smith, a 16 year-old junior at the Bushwick School for Social Justice, said in a statement released by the Dignity in Schools Campaign. The group is calling for a 50 percent reduction in suspensions by September 2013.

Schools Chancellor Dennis Walcott said a “safe environment is a top priority,” and that the city is working to prevent suspensions by addressing incidents before they escalate. He said the school system is also working to address the disparity in suspensions across race and ethnicity.

“This is a national problem, and in our schools we have implemented a pilot as part of the Young Men’s Initiative to reinforce positive behavior through coaching and problem solving,” he said in a written statement.