I've used stats for the basis of systems - they work well some weeks, but poorly on others.

the problem is in good races, there 5 horses or so that meet most of the criteria - so one needs to eliminate using other methods.

I normally look for
20% win rate, 50% place rate
50% place/win record at distance/track
one of the top prizemoney winners
finished within 3 lengths of winner last start.
good barrier and weight.

Does anyone here use speed ratings? - they work great in certain races