Jonathan Lovell says:
in a somewhat more nuanced study in January of this year entitled “What do international tests really show about U.S. student performance?” economists Martin Carnoy and Richard Rothstein come to a similar conclusion:
“The share of disadvantaged students in the U.S. sample was the largest of any of the [post-industrial] countries we studied. Because test scores in every country are characterized by a social class gradient—students higher in the social class scale have better average achievement than students in the next lower class—U.S. student scores are lower on average simply because of our relatively disadvantaged social class composition. . . [I]f we make two reasonable adjustments to the reported U.S. average, our international ranking improves. The first adjustment re-weights the social class composition of U.S. test takers to the average composition of top-scoring countries. The other re-weights the distribution of lunch-eligible students by the actual intensity of such students in schools. These adjustments raise the U.S. international ranking on the 2009 PISA test from 14th to 6th in reading, and from 25th to 13th in mathematics. While there is still room for improvement, these are quite respectable showings”
To put it succinctly, the “achievement gap” between American students and their foreign counterparts is largely a red herring.