Millions of students in the United States are still chronically absent from school after the COVID-19 pandemic, according to American news and opinion website Vox.

An estimated 7.3 million students were deemed "chronically absent" before the pandemic and the number of absent students has almost doubled after the pandemic, Vox reported.

Students are considered chronically absent when they miss 10 percent or more of the school year for any reason. The average school year for most schools across the country is 180 days long, which means that a chronically absent student typically misses at least 18 days of school or at least two days per month.

Data from Future Ed, an education think tank, shows that chronic absenteeism increased in every state where data was made public. In California, for example, the rate jumped from 12.1 percent in 2018–19 school year to 30 percent in the 2021–22 school year, meaning about three of 10 students in the state didn't show up as often as their teachers expected.

Considered a hidden educational crisis in the U.S., chronic absenteeism is not exactly new in the country. The causes of chronic absenteeism are vast, including poverty, illness, and a lack of child care and social services. It can influence a child's reading ability and lead to lower achievement and worsen long-term economic outcomes for individual students and the country.

The issue was mainly impacted students from disadvantaged communities, but experts pointed out that it now affects students from a variety of demographic backgrounds, from those in the suburbs and rural areas to those in cities.

Attendance Works is an organization that tracks attendance data and helps states address chronic absenteeism. Its founder and executive director Hedy Chang told the Vox that high levels of chronic absence show that the positive conditions of learning that are essential for motivating kids to show up to school have been eroded.

"It's a sign that kids aren't feeling physically and emotionally healthy and safe. Belonging, connection, and support — in addition to the academic challenge and engagement and investments in student and adult well-being — are all so crucial to positive conditions for learning," said Chang.

Students who are absent from school might not feel like they fit in socially and face anxiety as a result. An EdWeek Research Center survey conducted between August and September 2023 of more than 1,000 high schoolers found that anxiety, aside from bad weather, was a top reason they missed school. The National Institute of Mental Health also found that young people reported greater anxiety and depression after the pandemic. 

Studies have also found that when students find classroom lessons to be boring, unchallenging, or culturally unresponsive, they might stay away from school.

Some education leaders warn that the pandemic changed the way parents and students think about school and attendance is now viewed as optional for some parents.

States and localities are responding to the rise in chronic absenteeism, such as developing a home visit program and helping solve transportation challenges. But the problem still plagues school districts despite these efforts, indicating that battling it will take time and consistent effort.