Charter schools, which have recently come under scrutiny for high suspension rates, need to rethink school disciplinary practices, Secretary of Education John King plans to say Tuesday.

"Discipline is a nuanced and complicated issue," King says in remarks prepared for delivery during a speech Tuesday at the National Charter School Conference in Nashville. "Yet the public discussion of these issues is often binary – pitting one extreme against another. It's 'zero tolerance' or chaos. Authoritarian control or no discipline at all."

Charter schools, including some of the most well-known and heralded like Success Academy, Achievement First, Kipp Academy and others, are known for their zero-tolerance policies. Leaders say it's essential to ensuring success for the types of students they serve – students who typically live in economically devastated communities, who come to school hungry, who are being raised by a single parent or by their grandparents and who have no structure in their lives outside school.

But such policies can result in high suspension rates and are often criticized for pushing out the students who need the most help.

Indeed, a recent analysis from the Center for Civil Rights Remedies at UCLA found that, on the whole, charter schools have higher suspension rates than traditional public schools, and that students of color and those with disabilities are suspended at charter schools at higher rates than their peers.

Moreover, that study also found that Roxbury Preparatory Academy – a school that's been praised for its students' academic performance and one that was co-founded by King himself – boasted a suspension rate of 40 percent, the 12th highest-suspending school in Massachusetts.

King's call on the sector to rethink disciplinary practices also comes on the heels of a school year in which a flurry of media reports revealed some harsh forms of punishments being used by teachers.

"In every school, no matter how successful, we know there is more we can do to reach the students who are not yet succeeding and more we can do to equip students with not just the fundamental academic skills but the socioemotional skills needed for success in life," King says in his remarks.

In the waning months of the Obama administration, King and his team have taken a keen interest in pushing all schools to reassess disciplinary practices, noting that suspended students are less likely to graduate on time, and more likely to repeat a grade, drop out of school, and enter the juvenile justice system. Students of color are also more likely to be disciplined with out-of-school suspensions than their white peers.

The Education Department's Office for Civil Rights recently unveiled new data from the 2013-2014 school year that show nationwide 2.8 million K-12 students received one or more out-of-school suspensions. More troubling are the racial disparities in the data: Black students are 3.8 times as likely to receive out-of-school suspensions as white students.

King plans to underscore in his speech Tuesday that the charter sector, like traditional public schools, has shown improvement in the area of school discipline. The Office of Civil Rights data set, for example, showed that the number of students suspended during the 2013-2014 school year dropped 20 percent compared to the 2011-2012 school year.

But the large reduction in suspensions had little to no impact on racial disparities and also didn't budge the number of overall suspensions at the preschool school level, where black preschool children are 3.6 times as likely to receive one or more out-of-school suspensions as white preschool children.