First of all you need to make sure your ratings/points have been compiled with a statistically valid method.

I have attached a sheet that shows how many points or weighting would be assigned for a Factor or each individual rank within a Factor.
I think I may have posted this a long time ago, it shows the weight of the Factor and the ROE just check the ROE +/- against your selected confidence level

Remember you need to measure your handicapping with Strike rate and Wagering with ROI.

The general public odds need to be converted to Natural Odds.

Your rated 20% chance indeed needs to win 20% of the time, this in itself is very hard to measure, as it is very rare that you will get a large enough sample of exactly 20% rated chances to test a small deviation makes a large difference.

Also your rated 20% chances if you had a large enough sample would win 20% of races right thru all the odds ranges. ie if I had 100 of these .20 chances and they started at even money i'd expect them to win 20 races with a normal variance.
hopefully this is understood.

Attached Files

zscore2l.xls (18.0 KB, 805 views)