From the WSJ:

The PISA assesses student learning of 15-year-olds around the world every three to four years. While performance in most countries has declined since 2018, math scores in China have improved by an impressive 21 points (equivalent to roughly one year of learning) while those in the U.S. have fallen by 15 (three quarters of a year of learning).

As a result, the math skills gap between U.S. and China students has grown to the equivalent of more than seven years. Ponder that for a moment. While 8% of U.S. students rated “top performers” in math, 54% did in mainland China. Wonder why U.S. employers seek to hire high-skilled workers from abroad?

U.S. schools simply aren’t producing enough students with advanced engineering and math skills. A report last year from the University of California, San Diego, found that one in 12 freshmen had math skills below middle-school level.

The teachers’ union response to evidence of learning decline is always to spend more on public schools, but the gusher of federal K-12 spending during the pandemic didn’t improve performance. The PISA report notes that the relationship between a country’s wealth and test scores “is not linear and it flattens among those with relatively higher national incomes.”

Once cumulative spending per student from ages six to 15 exceeds roughly $85,000 per student—all U.S. states spend more than that—the relationship with student scores begins to “decouple.” “Higher spending per student does not automatically relate to higher performance scores,” the report says. Maybe because more spending rewards education failure, rather than success.