I'm not saying that this is the be all of selection systems, nothing is fullproof, but it does weed out a lot of losers, especially those that are very short. A horse that is say 5/1 in the paper could open at 9/2 but still drift to 10/1.
As an example, Saturday's results were Sydney 6/8 opened shorter than the PP (paper price) & Melb also 6/8. Of course it's not much help when there are 14 runners & 12 of them open shorter, but looking at overall winners to runners % it can give you an edge. In Syd & Melb there were 163 runners for 16 winners, around 10%. Those that opened shorter there were 96 runners for 12 winners, 12.5%. Those that opened longer, 67 runners for 4 winners or 6%. It may seem a little but those little bits add up in the long run. I've just realised that included in the "shorter" openers are those that open at the same as the PP. Taking this group on their own gives you 19 runners for no winners, and makes the shorter openers 12 from 77, or 15.5%.
Now if you liked something that was 10/1 PP & it opened at 12/1, I would never say don't back it, but if you liked something that was 6/4 & it opened 7/4, I would be thinking twice about it. A quick look at Saturday shows that there were 19 runners PP at 3/1 or less. Of these 13 opened the same or longer, for 2 winners @ 6/4 & 4/1, a big loss.
As most would know I only bet on races where I can back them all, but I have incorporated the above info into what I do & increased my POT.
:grin: