THE NATIONAL GROUP Attendance Works released state-by-state school attendance data and data for the nation’s 21 large, urban districts. In the report issued last week, the authors say school absenteeism is a national challenge.

Almost a half-million Michigan students missed more than 11 days of school in the 2012-13 school year. About 28.5 percent of all public school students in the state — some 438,312 kids — were chronically absent, according to data from the Center for Educational Performance and Information (CEPI), in the most recent year for which that data are available.

Missing several days of school each year can put students a least a year behind their peers in academic performance, according to a report released this week by Attendance Works.

“Going to school every day is a good habit to teach kids early,” said Phyllis Jordan, spokeswoman for Attendance Works.

Nationwide, 19 percent of the fourth-graders and 20 percent of the eighth-graders who took the exam in 2013 said they had been absent three or more days in the month leading up to it — which is how the group defines poor attendance.

Attendance Works report authors say their research shows that school attendance and student achievement are intertwined. The authors say it’s important to intervene as soon as absences begin to pile up.

The report’s authors also say that students from low-income homes are more likely to have poor attendance.

In Detroit public schools, 30 percent of fourth-graders and 33 percent of eighth-graders reported poor attendance. And in Michigan, 22 percent of fourth-graders and 21 percent of eighth-graders had poor attendance.

In Ann Arbor 29.7 percent of the district’s students—4,962 kids—missed 11 days or more of school in 2012-2013. Around the county, Whitmore Lake, Chelsea, Dexter and Saline Public Schools all posted better student attendance rates. In the Lincoln Consolidated District 80.2 percent of students missed 11 or more days of school.