RELISHA RUDD missed more than 30 days of school, some of them excused absences, before authorities suspected something was amiss. Chronic absenteeism is a troubling norm of public education in the District. Just as it served as a red flag of something terribly wrong in this still-missing 8-year-old’s life, it also is a powerful indicator of whether a child will succeed in school. That’s why it is important that city and school officials adopt a smarter approach to school attendance.

“In some of our schools, the number of kids who have the same number of absences as Relisha is astounding. It’s a problem,” D.C. Schools Chancellor Kaya Henderson told Post reporters who examined the issue. Last year, according to The Post’s account, nearly 40 percent of students in traditional schools missed at least 18 days of school, a figure that includes both excused and unexcused absences. Half of those students were absent for the equivalent of seven weeks in a school year of 36 weeks. Analysis by the nonprofit DC Action for Children that looked at both charter and traditional schools called the situation a “crisis,” with at least one in five students having more than 10 unexcused absences in 2012-13.

Missed school days translate into academic risk. Research shows that students with a significant number of absences in kindergarten and first grade won’t be reading on grade level at the end of third grade, setting them up for difficulty in the years ahead. Absenteeism in sixth grade is a red flag that a student will drop out of high school. Students who live in poverty and are most at-risk academically have the highest absenteeism rates.

Much of the District’s effort in recent years has concentrated on truancy — or unexcused absences — and punish parents and students who don’t comply with school rules. It’s an approach largely dictated by legislation from the D.C. Council. But groups including DC Action for Children and Attendance Works say more effective strategies center on better measures to identify students who are chronically absent (both excused and unexcused) and to determine any broad patterns that need to be addressed systematically. New York City, which has a model program, found, for example, that providing safe transportation in areas with gang problems helped students get to school and that making inhalers available to students with asthma increased attendance.

The work must begin as early as pre-kindergarten to help establish a culture of school attendance. Schools don’t have to do this alone. In New York, city workers serve as mentors for chronically absent students, and in Oakland, Calif., housing authority workers make it part of their job to see students off to school. Parents, of course, play a huge role, and that’s why more should be done to show them how two, three or four missed days a month add up to a bigger deal than they may think.