A report released Tuesday found that 4 percent of school districts nationally hold half of the nation's chronically absent students, including some in the Twin Cities metro area.

The students who are chronically absent are clustered in 654 districts, including local ones — Minneapolis, St. Paul, Anoka-Hennepin, Rosemount-Apple Valley-Eagan, Osseo, South Washington County, Stillwater and Robbsindale. Outside the metro area, the St. Cloud, Rochester and Bemidji districts made the list.

The results came from an analysis by Attendance Works, an initiative that advocates for better attendance policy, and the Everyone Graduates Center at Johns Hopkins University, which champions student success. They crunched numbers from the 2013-2014 chronic student absence data from the Office of Civil Rights, which was released in June. In that OCR data collection, chronic absence is defined as missing 15 or more days.

Students chronically absent from school miss so much class time that it puts them at risk academically. It can especially hurt children in poverty, whose families might not have enough resources to fill in for missed school.

More than 6.5 million students, or around 13 percent, miss three or more weeks of school, "which is enough time to erode their achievement and threaten their chance of graduating," according to the report.

About half of the districts identified "were modest to large urban districts." A 45 percent chunk was suburban districts. "While their rates often were close to the national average, their large numbers reflect the sheer size of each district and their growing populations of low-income students," the story map accompanying the report said.

metro-area district percent chronically absent Minneapolis 22.36% St. Paul 16.72% Anoka-Hennepin 6.52% Rosemount-Apple Valley-Eagan 6.66% Osseo 14.33% South Washington County 9.95% Stillwater 24.54% Robbinsdale 15.61%