In many schools, it's not unheard of for principals and teachers to offer small prizes or pizza parties as an incentive to convince more students to aim for perfect attendance.
State officials in Washington even recruited Seattle Seahawks and Sounders players to record robocall messages that school districts can use to wake students up and remind their parents about the importance of regular attendance.
But new research from Harvard University and the University of California, Berkeley, suggests a much simpler approach — one that has captured the interest of the Seattle Housing Authority and yields a big impact on efforts to reduce chronic absenteeism in school.
"It turns out, there is no silver bullet," said Todd Rogers, a public-policy professor at Harvard.
"We're not going to solve every problem, but what we're going to do is shave 10 to 2o percent of the problem super easily and inexpensively so that you free up resources to go after the harder stuff," Rogers said.
In a paper recently published in the journal Nature Human Behavior, Rogers and UC Berkeley professor Avi Feller found that mailing so-called "nudge" letters to parents when their students miss too many days of school reduces chronic absenteeism by 10 percent or more.
The researchers, working with schools in Philadelphia, randomly assigned about 28,000 students into four groups, two of which received one of two versions of a nudge letter: one that included a tally of how many days of school the student missed, and another that compared that tally to a class average.
A third group received a generic message that absences, excused or not, make a difference in how much a student learns. And a fourth, control group received no letter at all.
In the families that received the nudge letters, chronic absenteeism rates fell 10 percent. The researchers also found a spillover effect: Attendance improved for siblings of students targeted by the mailing.
"There are increasing treatment effects, with each additional mailing," Rogers said. "So as the year goes on, the effects get bigger."
He also stressed that the Philadelphia experiment and its results have been duplicated elsewhere.
In a separate working paper published last year, Rogers and a team of researchers from Harvard and Stanford universities and Boston College tested the nudge letters at 10 school districts in one diverse California county. That intervention reduced chronic absenteeism by 15 percent in the elementary grades.
Nudge letters have also reduced chronic absenteeism by 11 percent in Chicago Public Schools, according to In Class Today, a for-profit organization Rogers co-founded to help districts interested in the approach.
In Washington state, Tacoma Public Schools tried a pilot of the nudge letters. District officials there credited the letters for a 62 percent boost in attendance at the pilot school, convincing them to expand the effort to every campus this school year.
Nudge letters also captured the attention of the Seattle Housing Authority (SHA), which houses about 10 percent of students enrolled in the Seattle school district.
"For a number of years we've been doing letters from the Housing Authority around the start of school. Make sure you're ready for school, attendance is critical, that sort of thing," said Kerry Coughlin, an SHA spokeswoman.
This year, SHA started personalizing its letters to families with chronically truant students. And in a preliminary analysis of attendance data, SHA found chronic absenteeism among students living in subsidized housing fell 24 percent during the first four weeks of the 2017-18 school year compared to the same period in 2016-17.
"Our commitment to this continues," Coughlin said. "It's something we definitely want to keep doing."