Researchers, policymakers, educators, and journalists have focused copious amounts of attention on student absenteeism data in the years since a pandemic-era surge that is only now beginning to moderate. Of particular concern is chronic absenteeism, nearly universally defined as missing at least 10 percent of school (generally 18 days) for any reason, and the potential academic harm missing so much school could cause. Research protocols , early warning systems , accountability structures , and considerable resource allocations to identify and reduce chronic absenteeism have all been calibrated with this definition as their guiding principle. However, a trio of researchers from the University of Michigan hypothesize that other measures might be more accurate in predicting negative academic outcomes—and indeed might reset the definition of “chronic absenteeism” in that regard. They set out to test their theory in a new working paper .