Average fourth-grade scores on the test’s 300-point scale rose slightly since the exam was last administered, in 2006, to 157 from 154. Average eighth-grade scores were virtually unchanged at 151. The scores of high school seniors — students who are either eligible to vote or about to be — dropped to 148 from 151. Those scores mean that about a quarter of 4th- and 12th-grade students, and about one-fifth of 8th graders, ranked at the proficient or advanced levels.

“The results confirm an alarming and continuing trend that civics in America is in decline,” said Charles N. Quigley, executive director of the Center for Civic Education, a nonprofit group in California. “During the past decade or so, educational policy and practice appear to have focused more and more upon developing the worker at the expense of developing the citizen.”

One bright spot was that Hispanic students, who make up a growing proportion of the country’s population and student body, narrowed the gap between their scores and those of non-Hispanic white students. On average, Hispanic eighth-graders scored 137 and non-Hispanic whites 160. That 23-point gap was down from 29 points in 2006. Among high school seniors, the gap narrowed to 19 points from 24 points.

The achievement gap between blacks and whites in civics, about 25 points at the fourth- and eighth-grade levels and 29 points among high school seniors, did not change significantly.