Just my personal view;  but I feel strongly that the smally the applicable "universe", the less value there in on an index based on that "universe".

 Large cap funds, or total market funds, the index is based on a very large sample size.

When you get to micro-cap-not USA based with value tilt funds,     well, I think you see my point.  Keep slicing up the universe and eventually you've an index based on a single actively managed funs!

//mjs