Nice article here from the good folks at Research Affiliates on picking managers with high active share.
There has been a lot of research that demonstrates funds selected based on active share outperform (and one of the reasons we like funds on AlphaClone that truly pick unique stocks like Baupost and ValueAct). (More here on how to pick mutual funds.)
Does Morningstar calculate active share for their funds? I can’t seem to find it but will update if I do. In the meantime, here is an Excel add-in to calculate active share on your own (I have not tried it).