The reason the US always ranks at the bottom of standardized test scores has nothing to do with how our education system works and everything to do with who it educates.

In virtually every other industrialized country, students are split into two educational tracks, one vocational and one for "real education" which roughly corresponds to the split in the US between kids who go to college and those who don't.

Standardized tests (like the ones whose scores are reported on here) are only given to the kids on the "real educational" track in other countries, while in the US they're given to everyone, and the inevitable result is that scores from the US take a big hit because of the non-college bound kids.

Once in a while you see a report where someone filters the test results for only honors or AP students in the United States before comparison, and in these comparisons US scores are pretty much the same as other industrialized countries.