Families’ interest in their kids’ education is falling in many high-income countries as school systems struggle with plunging test scores, according to newly released results from a standardized test taken by 15-year-olds around the world.

Over 760,000 teenagers in dozens of countries took the Programme for International Student Assessment last year. Results released Tuesday show average scores in math, reading and science are all at their lowest point in PISA history among highly developed economies. That includes continued declines in reading and math scores in the U.S.

China, Singapore, Taiwan, Japan and South Korea scored the highest marks on the test. Estonia, the United Kingdom and New Zealand also did well.

The key to why scores are falling so widely may be found in an accompanying survey taken by students.

Compared with the 2022 results, almost every country saw a drop in families’ support for their kids’ education, especially for boys, as measured by questions about how often parents talk to their kids about their schoolwork or take an interest in their learning.