Emma Brown

The nation’s high school seniors have shown no improvement in reading achievement and their math performance has slipped since 2013, according to the results of a test administered by the federal government last year.

The results of the National Assessment of Educational Progress, or NAEP, also show a longer-term stagnation in 12th-grade performance in U.S. public and private schools: Scores on the 2015 reading test have dropped five points since 1992, the earliest year with comparable scores, and are unchanged in math during the past decade.

“These numbers are not going the way we want,” said William J. Bushaw, executive director of the National Assessment Governing Board, an independent panel established by Congress to oversee NAEP policy. “We have to redouble our efforts to prepare our students.”

The sobering news, released Wednesday, comes at the same time the nation is celebrating its highest-ever graduation rate, raising questions about whether a diploma is a meaningful measure of achievement.

Eighty-two percent of high school seniors graduated on time in 2014, but the 2015 test results suggest that just 37 percent of seniors are academically prepared for college course­work in math and reading — meaning many seniors would have to take remedial classes if going on to college.

Related: Math Forum audio/video links.