but we don't

"Oh, Kay. Greg Mankiw looks at a graph showing that children of high-income families do better on tests, and suggests that it’s largely about inherited talent: smart people make lots of money, and also have smart kids.
But, you know, there’s lots of evidence that there’s more to it than that. For example: students with low test scores from high-income families are slightly more to finish college than students with high test scores from low-income families.
It’s comforting to think that we live in a meritocracy. But we don’t."

(Paul Krugman, Heredity, environment, justice)