Average scores for high school seniors have also remained flat since the last time the test, known as the "Nation's Report Card," was administered in 2009. The test, taken every four years by a sample of high school seniors and every two years by students in the fourth and eighth grades, aims to provide a snapshot of U.S. achievement.
The test was taken between January and March in 2013 by 92,000 high school seniors. Elementary and middle-school scores, released in November, showed some gains.
Education Secretary Arne Duncan reported recently that the average graduation rate for U.S. high schools had hit 80 percent, an all-time high. He said he was troubled by the flat high school scores on the NAEP and by the failure to close the gap between white and minority students.
Black students have fallen even further behind in the 15 years the test has been administered, while the gap between whites and Hispanics has not closed.
"We project that our nation's public schools will become majority-minority this fall -- making it even more urgent to put renewed attention into the academic rigor and equity of course offerings and into efforts to redesign high schools," Duncan said. "We must reject educational stagnation in our high schools, and as a nation, we must do better for all students, especially for African-American and Latino students."
Frederick Hess, an education analyst with the conservative American Enterprise Institute, suggested high school seniors may not be motivated to do well in a test that will not affect their futures. Hess told the Washington Post that U.S. officials tend to be "manic depressive" about test scores, hailing educational progress when they inch up and then throwing up their hands when they do the reverse.
“We all remember exactly how engaged your 17-year-old high school senior is,” Hess said.