WASHINGTON - The COVID-19 pandemic caused historic learning setbacks for America’s children, sparing no state or region as it erased decades of academic progress and widened racial disparities, according to results of a national test that provide the sharpest look yet at the scale of the crisis.

Across the country, math scores saw their largest decreases ever. Reading scores dropped to 1992 levels. Nearly four in 10 eighth graders failed to grasp basic math concepts. Not a single state saw a notable improvement in their average test scores, with some simply treading water at best.

Those are the findings from the National Assessment of Educational Progress - known as the “nation’s report card” - which tested hundreds of thousands of fourth and eighth graders across the country this year. It was the first time the test had been given since 2019, and it’s seen as the first nationally representative study of the pandemic’s impact on learning.

“It is a serious wake-up call for us all,” Peggy Carr, commissioner of the National Center for Education Statistics, a branch of the Education Department, said in an interview. “In NAEP, when we experience a 1- or 2-point decline, we’re talking about it as a significant impact on a student’s achievement. In math, we experienced an 8-point decline - historic for this assessment.”

Researchers usually think of a 10-point gain or drop as equivalent to roughly a year of learning.

It’s no surprise that children are behind. The pandemic upended everyday life and left millions learning from home for months or more. The results released Monday reveal the depth of those setbacks and the size of the challenge schools face as they help students catch up.

Education Secretary Miguel Cardona said it’s a sign that schools need to redouble their efforts, using billions of dollars that Congress gave schools to help students recover.

“Let me be very clear: These results are not acceptable,” Cardona said.

The NAEP test is typically given every two years. It was taken between January and March by a sample of students in every state, along with 26 of the nation’s largest school districts. Scores had been stalling even before the pandemic, but the new results show decreases on a scale not seen before.

In both math and reading, students scored lower than those tested in 2019. But while reading scores dipped, math scores plummeted by the largest margins in the history of the NAEP program, which began in 1969.