> Citation? All countries have a mix of wealthy, educated students, working class students, students whose parents are drug addicts, immigrants who don't speak the local language, etc. In my experience the US isn't that different from other wealthy countries I've lived in.

If you look at [0], It looks like the parent is right.

> However, the PISA’s results are drastically over simplified. For instance, as noted in a report by Dr. Martin Carnoy of Stanford and Richard Rothstein of the Economic Policy Institute, American students actually perform better than the much higher ranked Finland in algebra in general, but worse in fractions. More importantly, when you normalize the results between the countries, adjusting for the relative poverty of the students taking the PISA tests, the U.S performs significantly better, ranking 6th in reading and 13th in mathematics, a drastic jump in both categories.

> Dr. Carnoy and Rothstein further note in their report What Do International Tests Really Show About U.S. Student Performance? that when you divide the kids based on family wealth, the actual gap in performance isn’t so stark between any country, with a not insignificant portion of the ultimate ranking of each nation being based on how many impoverished vs. middle class vs. wealthy students are taking the tests.

[0] http://www.todayifoundout.com/index.php/2015/01/kids-get-sum...