JOANNE JACOBS: Dumber and dumber: Americans, young and old, are slipping.

“Americans are getting dumber,” writes Chad Aldeman on The 74. Achievement peaked about a decade ago on “a wide range of national and international tests, grade levels and subject areas.” Since then, students — and adults – are doing worse.

The pandemic made it worse, but the downward trend started years before lockdowns and zoom school.

Scores have fallen faster for lower-performing students, he notes. Achievement gaps, which were narrowing, are growing, points out Nat Malkus of the American Enterprise Institute. In a new report, he writes that “external societal factors — not just school-related influences —are at play.”

At the start of the decline, writes Aldeman, the Obama administration relaxed federal accountability rules. It would make sense to blame that — except that U.S. adults are doing worse in literacy and numeracy on international tests, with lower achievers again losing the most.

Just another case of the better-off closing doors of opportunity to potential competitors from the less well-off.

Thanks, Obama.