ok just got back to this thread and saw all the replies.

Value is getting better odds then the "true" chance of the horse.

If one ratings service has it at 2/1 and the other has it at 4/1 then one of these (or possibly both) has got the chance of the horse winning wrong.

The true chance of the horse might be 3/1 or it could be 6/1. You won't know until after many races. Historical figures give an indication on whether or not your rating gives the "true" chance of a horse winning but not always as the past doesn't always repeat in the future.

But if you want to know the best indicator of a horse winning then you should look at the price. No matter how many experts you look at the public is always better at determining the "true" chance of a horse. If a horse is starting at 3/1 then more than likely his chance of winning the race is 25%. Of course if your looking at the Tote then you really are looking at an 85% market so the chance is actually less than 25%.

Then if you can get higher odds then the tote (by at least 20%) then you are getting good value and will probably win longer term.

So now you are probably going to say this isn't going to help anyone because betfair usually only has horses at 10% - 15% higher than the tote. But as Chrome Prince pointed out a couple of days ago, if you look at the PPM selections you will get great value on the long shots at betfair and they can be more than double the "true" chance. This will eventually result in a long term profit.

Good Luck.