The latest Nation’s Report Card shows eighth-graders’ scores in U.S. history and geography declining since 2014.
Education Secretary Betsy DeVos on Thursday called the results “stark and inexcusable.”
Civics scores on the 2018 assessments were the same as in the last round of tests four years earlier.
The 2018 assessments were given for the first time digitally on tablets instead of paper to about 43,000 eighth-grade students in public and private schools.
Administrators say another troubling finding is that lower-performing students lost more ground than middle- and higher-performing students.
Experts fear the problem will be made worse by the ongoing loss of class time.