Math and reading scores have dropped to their lowest levels in more than two decades among high school seniors.

William Brangham reports on new test scores that have many educators and other experts concerned.

That's right, Omna. These scores come from the latest so-called Nations Report Card,

which is put out by the National Assessment of Educational Progress,

and it shows that student achievement has continued to decline significantly since the pandemic.

Among high school seniors, the average reading score last year was the lowest since the assessment

began in 1992. What's worse, nearly a third of seniors did not have the basic reading skills

needed to find the details in a given text to understand its meaning. Average math scores also

slip to their lowest levels since 2005. There are many theories about what is going on here,

and so to explore some of that, we are joined by Thomas Kane.

He's a professor of education at Harvard's Graduate School of Education.

Thomas Kane, thank you so much for being here.

Somewhat of a broad question for you, but what is your best assessment as to why these scores are so low and continuing to decline?

So, first of all, these latest results are not surprising, unfortunately.

Our research center has been tracking trends for individual districts around the country

for the last three or four years. What is new is the degree to which

these losses are concentrated among the lower achieving students. So the 10th percentile student in the

U.S. has lost about two great equivalents since 2015. That's a large loss. And, you know, it'll be equivalent to about

5% of lifetime earning. So this would have impacts on future income inequality if we don't

reverse it. So can you run us through what the sort of principal theories are as to why we are in

the state we're in? There are three hypotheses to explain what's been happening.

Number one is there's been a decline in focus on test-based accountability since the No Child

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