I've been particularly interested in all of the active share research and have spent time speaking with Professor Cremer, one of the original authors of the first active share research, on multiple occasions. I think it is important to consider the motivations behind AQRs paper when making a conclusion as to the validity of their claims. While the same data was used to support AQR's conclusions it was organized in a much different way. Both of the original authors have written responses to AQR which I think are worth considering before drawing your own personal conclusion.

Here are links to the responses:

http://www.petajisto.net/papers/petajisto%20response%20to%20AQR%20artic…

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2625214

In addition, there has been more research done combining active share with measures of patience for active managers which result in more statistically relevant conclusions. Here is the link:

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2498743

Active share is obviously one tool of many used in evaluating mangers but as with everything else it is important to be as impartial as possible and evaluate as much information as you can find before determining whether you want to incorporate it into your own research.