Levitt is famous for suggesting that the dramatic decrease in the crime-rate is due to legalizing abortion. He makes all kind of connections like this in his book, Freakonomics. Some are amusing, some interesting, some obvious, and some nonsense.
The analysis of who is voted off in "The Weakest Link" was very interesting. I also liked the segment on picking up children late from daycare. The nonsense came under the chapter on Parents Don't Matter. To measure parent effectiveness by how well children do in school, seems awfully shallow. He collapsed all parents who work before the child starts school into one group and said it made no difference. Well, probably it doesn't as a group. You are going to get parents who work for different reasons, and when you control for that, it really does make a difference - even on something as shallow as school success.
This was in stark contrast to an article I have just read in the Journal of Consulting and Clinical Psychology on how an adolescent's behavior is so profoundly influenced by having a parent die of AIDS. Well, actually, the worst problems are in the year before the parent dies. After the parent dies, the child usually is moved to a more stable environment and life settles down a little.