A new international study showing a significant drop in U.S. students’ math test scores is raising concerns over student performance.

The National Center for Education Statistics, or NCES, released highlights from the Trends in International Mathematics and Science Study, also known as TIMSS, on Wednesday, which offers a snapshot at how many students are behind in mathematics and science, both critical subject areas.

Between 2019 and 2023, test scores for American fourth graders in math dropped by 18 points and scores for eighth graders dropped 27 points. Overall, math test scores stagnated, remaining comparable to math test scores from 1995, when the TIMSS began to be administered to students.

In addition, fourth grade and eighth grade boys outperformed girls on math and science tests in 2023 according to TIMSS results, highlighting persisting gender gaps in different academic subjects.

“The results are sobering,” NCES Commissioner Peggy G. Carr told ABC News. “We started this assessment in 1995, so we have, essentially … erased the gains that we were seeing for decades.”

When compared with students in other countries, students in the U.S. are only in the middle of the pack and behind students in Asian and European countries including Singapore, Japan, the United Kingdom and Poland, according to TIMSS results.

Education experts cited the COVID-19 pandemic as a major reason for the decline because schools were closed or disrupted in the U.S. for longer than in other countries and pointed to absenteeism as another notable problem.

But Carr said the pandemic wasn’t the main cause of such a noticeable decline in students’ knowledge and performance.

“This decline that we’re seeing was there in 2015, so all of this cannot be blamed on COVID,” the commissioner said. “We have been struggling with declining scores, particularly in math, for a while.”

“We need to focus on the students that have been struggling for a while now, and that is where I want to leave it for us as a country to sort of ponder,” Carr added.

Other countries, with help from parents, have changed their curricula in recent years to try to make math more fun for young learners and shift the focus away from formulas or focus on creativity and problem-solving more.

Experts say if parents think their children are struggling with math or science, they should talk to their teachers about what resources might be available, such as after-school programs or any extra online coursework that parents can work on with their kids.