How many school days a student misses during the month of September can predict how often he or she will show up for classes for the entire year, and in the school years ahead. Chronic absenteeism is a downward spiral, which, left unchecked, affects whether a child develops the grit and perseverance needed to succeed in school, from preschool on through college.

The issue is an urgent one for Hawaii’s public schools, where a new study found that fourth- and eighth-graders were more likely than the national average to be chronically absent, and that the time out of class adversely affected their academic performance even more acutely than it did in other states.

The report, "Absences Add Up: How School Attendance Influences Student Success," by the advocacy group Attendance Works, contains a state-by-state analysis of chronic absenteeism — defined as missing three or more school days a month — and its negative impact on student learning as measured by the National Assessment of Educational Progress (NAEP).

As in other states, Hawaii students who missed the most school performed worse on the standardized test in 2013. Hawaii had a higher percentage of students who were chronically absent than the U.S. average, and the NAEP "scoring difference" between students who missed a lot of school and those who didn’t was among the highest in the nation. This gap suggests that chronically absent students lag one to two years behind in reading and math skills compared to their better-attending peers.

As stark as these finding are, they offer the glimmer of hope in a state like Hawaii, with a single school district that recently has devoted a lot of energy to reducing chronic absenteeism. Hawaii is one of only 17 states that tracks chronic absenteeism, recognizing that regular school attendance is one of the most powerful predictors of student success, even after accounting for other factors such as poverty and disability.

The Department of Education has made improving attendance a key factor of its Strive HI Performance System, and points to great improvements in just the last year, thanks to a combination of public awareness campaigns instilling in parents and children the importance of regular attendance; curricular and instructional upgrades to make school more engaging, and other improvements.

During the 2013-14 school year, the percentage of students who were absent 15 days or more dropped to 11 percent from 18 percent the year before — a significant change that signals greater student achievement ahead, perhaps even higher graduation rates, if those students maintain good attendance.

It’s crucial to break the cycle of poor attendance early, because students who are chronically absent one year are 35 percent more likely than their peers to be chronically absent the next — and ultimately are more likely to drop out of school altogether.

As the study highlighted, the issue is especially important in Hawaii, where higher academic standards and a more rigorous Common Core curriculum mean that every minute in class counts. The larger-than-average NAEP score gap makes plain that instruction is moving along at a faster clip and students who miss even a day or two a month are missing out on a lot.

The good news is that Hawaii has the comprehensive data-collection system needed to serve as an early warning to parents and teachers when absences are adding up. It’s up to parents and guardians to heed the warnings, and to recognize that the habits formed in kindergarten may help — or hinder — a child for life.