D.C. Public Schools Chancellor Kaya Henderson (Katherine Frey/Post)

Fewer students were chronically truant this year from the District’s traditional public schools, but absenteeism is still a rampant problem at many high schools, Chancellor Kaya Henderson told the D.C. Council Monday.

“It is clear that we need a different approach to successfully address high school truancy,” Henderson said, outlining an effort to focus “specifically and immediately” on ninth-grade students, who have among the worst attendance citywide.

Overall, the proportion of DCPS students who missed three weeks of class or more fell from 11 percent during the 2011-12 school year to 8 percent in the 2012-13 school year.

The change came as schools officials, pressed by the council to take action, convened “student support teams” to help families address the root causes of children’s absenteeism. Officials also complied far more often with a law requiring that truants be referred to the city’s child welfare agency or court social services.

Referral seemed to spur improved attendance for younger children ages five to 13. About half of students referred to child welfare went on to accumulate fewer than five unexcused absences throughout the rest of the year.

But older students ages 14 to 17 were not as likely to change their behavior. More than half of those teens who received referrals went on to accumulate more than 15 additional unexcused absences.

At Anacostia High, six in 10 students missed more than a month of school this year, up from 45 percent last year, said Council Member David Catania (I-At Large). At Ballou, 58 percent of students missed that much class, up from 46 percent last year. Rates also ticked up at schools including Cardozo, Coolidge and Woodson, Catania said.

Henderson said she aims to reduce those truancy rates by changing the trajectory of freshmen, who she said often disengage after struggling with high school-level academics.

Nine high schools across the city will open this fall with “ninth grade academies” dedicated to instructing first-time freshmen. Each will be run by a team of teachers, and a a counselor and social worker, all tasked with ensuring that students have the extra support and guidance they need to get off on the right foot as they enter high school.

Henderson said she would follow up with the council to provide more information about the cost of the initiative at each school. A school system spokeswoman said it would cost $2 million in federal Title I funds.

Freshmen who have already failed the ninth grade will not be allowed to enroll in academies. They may participate in online credit-recovery programs or afternoon “twilight” classes meant to help students quickly earn the credits they need to catch up with their peers, officials said.

Henderson said the school system will also be more aggressive about requiring the furthest-behind students to attend alternative schools such as Luke C. Moore Academy or one of two STAY programs.