Reading scores for elementary school students plunged to their lowest levels since 1990 during the first two years of the pandemic — and math scores dropped for the first time in the history of a nationally representative test dating back to the 1970s.

Why it matters: The national test results out Thursday lay out the extent to which the pandemic devastated learning outcomes for America's students, particularly for those who were most vulnerable even before the pandemic.

• "These are some of the largest declines we have observed in a single assessment cycle in 50 years of the [National Assessment of Educational Progress] program," acting associate commissioner Daniel McGrath said in a statement.
• "Students in 2022 are performing at a level last seen two decades ago."

Driving the news: The findings by the National Assessment of Educational Progress showed a 7 percentage point drop in math scores among 9-year-olds, mostly fourth graders, and a 5 point drop in reading scores.

• The tests were administered from January to March in 2020 and 2022.
• The decline in learning outcomes were starkest among lower-performing students.
• Top-performing students — those in the 90th percentile — showed a 3 percentage point drop in math scores, compared with lower-performing students — those in the 10th percentile — experiencing a 12 point decline.
• Math scores for Black students fell 13 points, compared to a 5 point decrease among white students.

Between the lines: Of the 70% of test takers who said they learned remotely last school year, higher performers had greater access to resources more often, including a desktop computer or a quiet place to work, compared to lower performers, per the results.

The big picture: The test results are considered a reliable snapshot of student learning outcomes because the assessments are standardized nationwide and because the test has remained consistent, the New York Times notes.

• Students' scores have generally ticked upward since the 1970s, when the test was first administered, but in recent years the increases have waned slightly, per the Times.

State of play: The pandemic disrupted virtually all aspects of the educational experience — and experts warn that the daunting task of student recovery could take years.

• "Unless we act over the next couple of years to reverse these losses, this will be the first significant widening of the racial achievement gap in 30 years," Thomas Kane, a Harvard economist who has done extensive research on the pandemic achievement loss, said in a Harvard EdCast interview.

Go deeper: Schools look to get back on track after 2 terrible years

Editor’s note: We corrected the name of the National Assessment of Educational Progress.