YM and EX e-mini made for some nice gap fade setups today. I use Master the gap to help me gauge if I am going to gap fade and index.
Some of the statistics you receive are the percentage a gap will fill in a certain zone and its profit factor. For example today the YM (dow e-mini index) had a 83% chance to fill its gap with a 2.12 profit fact for the zone it opened up in today. (this is taken over a ten year period)
Again I highly recommend Master the Gap and always use a stop.