Eduarto Porter has an excellent column on that topic, here is one bit:
In a report released last week, Martin Carnoy from the Graduate School of Education at Stanford, Emma García from the Economic Policy Institute in Washington and Tatiana Khavenson from the Institute of Education at the Higher School of Economics in Moscow, suggest that socioeconomic deficits impose a particularly heavy burden on American schools.
“Once we adjust for social status, we are doing much better than we think,” Professor Carnoy told me. “We underrate our progress.”
The researchers started by comparing test scores in the United States with those in France, Germany, Britain, Canada, Finland, South Korea, Poland and Ireland. On average, students in all those countries do better than American children.
Then the researchers divided students into groups depending on the number of books in their homes, a measure of the academic resources at families’ disposal. This adjustment significantly reduced the American deficit, especially among students on the bottom rungs of the resource ladder.
American students from families with the least educational resources, as it turned out, scored better on the PISA math test than similar children in France and about the same as Britons, Germans and Irish.
Read the whole thing.