Chronic absenteeism in public schools surged during the pandemic, which experts say helps explain a historic plunge in student test scores.

At least 10.1 million students were chronically absent during 2020-2021, the first full academic year of the pandemic, according to federal data analyzed by researchers at Johns Hopkins University and the nonprofit Attendance Works. That’s 25 percent more than the typical 8 million chronically absent students each year.

But early data from a handful of states during the pandemic’s second full school year shows that absenteeism may have dramatically worsened. Rates will probably double, compared with the pre-pandemic year, researchers said – an “alarming” increase. And that has clearly driven down tests scores, they said.

“If kids are getting less instruction, or less-consistent instruction, you’re going to learn less and you’re going to be able to answer fewer questions on the tests,” said Robert Balfanz, a professor of education at Johns Hopkins University and director of its Everyone Graduates Center.

Already, four states – Connecticut, Ohio, Virginia and a subset of California – have posted figures for 2021-22 that show the doubling that he and others predict. National data for that year has not yet been released, but researchers said data from school systems in other states showed similar spikes.

The soaring rate of chronic absenteeism converges with striking declines in scores on the National Assessment of Educational Progress (NAEP), often called “the nation’s report card.” Federal officials called the stark declines “historic” when they were released.

Test scores in elementary school math dropped seven points, marking a first-ever fall, while reading scores slipped five points, producing the largest dip in 30 years. The results, made public Sept. 1, were the first nationally representative comparison of student achievement from just before the pandemic to that two years later. Students who took the test were 9 years old and mostly in fourth grade.

Students are considered chronically absent when they miss more than 10 percent of school days for any reason – unexcused or excused absences, or suspensions – which research links to serious consequences: They are less likely to read on grade level by third grade, and more likely to score lower on standardized tests and get suspended in middle school. They are at greater risk of dropping out of high school.

Researchers also created a state-by-state comparison, showing a wide range of chronic absenteeism. The highest rates, of more than 30 percent statewide, were reported in Kentucky, Arizona, Nevada, Rhode Island, Oregon and New Mexico.

Zeroing in on even one state is sobering, Balfanz said. In Kentucky, an extra 116,537 students were chronically absent in 2020-21, compared with the pre-pandemic year of 2018-19, with 118,795 students swelling to 235,332. “This is a lot of kids missing a month or more of school,” he said.

Many students with low NAEP scores reported more technology difficulties or other challenges during months of virtual and hybrid instruction during the pandemic. Lower-performing students as a group had less access to a computer all of the time, a quiet place to work some of the time, and daily or near-daily support from a teacher.

Those setbacks, in turn, also affected attendance, said Hedy Chang, executive director of Attendance Works, which worked with Balfanz and Vaughan Byrnes, a senior research associate at the Johns Hopkins center. “If you don’t have a computer, you can’t show up,” she said. “If you don’t have internet, you can’t show up.”

Especially during the pandemic, chronic absenteeism has been extremely underreported, Chang said. States and school systems shifted definitions of student attendance in major ways – particularly when classes were held remotely. In 2020-21, Connecticut required students to spend half the day in a range of learning activities to be counted as present, while Alaska considered remote learning like a correspondence course, so students did not have to log on.

Teachers around the country have also said that even if students signed on, it was hard to tell if they were really listening because so many turned off their computer cameras.

During the second full year of the pandemic, other problems had an effect. Many students were out at the beginning of the year and just after the holiday break because of COIVD surges and quarantines. Teacher and staff shortages also were rampant.

Chang urged school systems to closely monitor student attendance, and to intervene with students who miss more than two days a month. “They need extra outreach and support,” she said, to avoid experiencing the worst effects of missing school.