This article is the biggest bunch of rubbish that I have read in months. It takes bias to whole new levels. People are starting to realize that "studies" are almost always biased in the first place and should not be trusted. Secondly, look at some of the examples used:
A comparison is made between:
25% of black kids had parents who grew up in the bottom two levels* and moved up at least one.
and
59% of white kids moved up
Notice any difference here? The whole article is like this. Comparing completely separate things. This is laughable. I feel embarrassed by the bias and sorry for those who read this article with a straight face.