High school seniors had the worst reading scores since 1992 on a national test, a loss probably related to increases in screen time and the pandemic. Their math scores fell as well.

The reading skills of American high school seniors are the worst they have been in three decades, according to new federal testing data, a worrying sign for teenagers as they face an uncertain job market and information landscape challenged by A.I.

In math, 12th graders had the lowest performance since 2005.

The results, from the National Assessment of Educational Progress, long regarded as the nation’s most reliable, gold-standard exam, showed that about a third of the 12th-graders who were tested last year did not have basic reading skills.

It was a sign that, among other skills, they may not be able to determine the purpose of a political speech. In math, nearly half of the test takers scored below the basic level, meaning they may not have mastered skills like using percentages to solve real-world problems.

The test scores are the first of their kind to be released since the Covid-19 pandemic upended education. They are yet another sign that adolescents are struggling in the wake of the virus, when schools were closed for months or more. They also arrive at a time when Americans overall are abandoning printed text for screen time and video-dominated social media, which experts have linked to declining academics.