Maybe, maybe not. One reason U.S. public school test scores are abysmal is because many other nations refuse to test or even school the lower functioning students the U.S. include in its own scores.
There's some truth to that. After 8th grade, a lot of nations move the brightest into college prep (what we'd call "high school") and the rest into vocational ed.
So the apples-to-apples comparision is how our 8th graders match up to those of other nations in the same subjects. So the International Math and Science Study gives 8th graders identical tests in math and science. Here's how we match up:
Math:
- Singapore 606
- Korea 605
- Chinese Taipei 591
- Japan 585
- Northern Ireland 562
- Belgium (Flemish) 549
- Finland 545
- England 543
- Russian Federation 542
- United States 541
Tenth of 50 nations overall.
Science:
- Singapore 590
- Taiwan 564
- South Korea 560
- Japan 558
- Finland 552
- Slovenia 543
- Russia 542
- Hong Kong 535
- England (and Wales) 533
- United States 525
Again, tenth of 50, (last testing 2011)
Details here:
http://timss.bc.edu/timss2011/index.html
In both, well above average. Not that tenth is where we want to be, but no nation with an immigrant population as large as ours has comparable scores.
That is NOT the only reason the U.S. has low test scores but it should be factored in when comparing us to other nations who don't count those kids.
TIMSS in 8th grade, pretty much eliminates the factor you're talking about. And yeah, we look pretty good. Not good enough, but well above average.
And that's due mostly to a few states with either many, many immigrants, (language-related issues or poor previous schooling) or low state education budgets (mostly deep south).
Some states in the US compare well with the best countries in the world. Lacking a national education policy, that probably won't ever be the norm.