Stephen Pettigrew and Reuben Fischer-Baum, for Regressing, compared 11 million brackets on ESPN.com against those of pundits.
To evaluate how much better (or worse) the experts were at predicting this year's tournament, I considered three criteria: the number of games correctly predicted, the number of points earned for correct picks, and the number of Final Four teams correctly identified. Generally the experts' brackets were slightly better than the non-expert ones, although the evidence isn't especially overwhelming. The analysis suggests that next year you'll have just as good a chance of winning your office pool if you make your own picks as if you follow the experts.
Due to availability, the expert sample size is a small 53, but it does appear the expert brackets are somewhere in the area of the masses. Still too noisy to know for sure though.
If anything, this speaks more to the randomness of the tournament than it does about people knowing what teams to pick. It's the same reason why my mom, who knows nothing about basketball or any sports for that matter, often comes out ahead in the work pool. The expert picks are just a point of reference.