I've read many times on here that one of the most valuable filters is the type of race.

Early days, but my Win% system is getting rid of losers when I eliminate horses that haven't run in anything equal to or better than a Handicap race. I include the Group races, Stakes, Open and Handicap. I've never used this filter before but it seems logical with a "stable" type selection method as you're going to get a better class horse (confidence of it's potential by the trainer's placing of it), with a decent strike rate.

Not sure what other systems could benefit from this filter, not too many spring to mind actually.

Just thought I'd share this for the unwashed amongst us .....