The only way to assign ratings and the value thereof under varying scenarios, is to have a significant database with reliable statistics.

I have just got myself a database and you would be surprised the relative importance of some factors on profit, not strike rate have.
Similarly, you'd be very surprised how relatively insignificant some data is to filter losing bets.

E.G. Barrier position has very little impact on a large sample of data. Now whether you want to filter it to different scenarios, like front runners and distance is another thing, but overall I'm speaking, barriers have a minute impact on success or failure.

Database is the only way to go if you want to take this seriously.

Good Luck.

[ This Message was edited by: Chrome Prince on 2003-03-06 23:13 ]

Chrome: I am assuming that the rating I have includes a consideration of all of the important factors influencing the result which have been used to create a numerical rating. I want to convert ratings to odds. A mean rating and Z score does not convert the rating to a probability of the horse winning, rather it gives the probability that a numerical rating is exceeded. It is not clear how the difference rating scores connected to the frequency of the number of times A beats B gives the probability that a wins. Maybe A and B have never raced.

Vig,

although you've managed to figure out that the other methods are unsuitable, why do you insist on ignoring my method which clearly works and I believe is the only practical approach?

Now, much as I despise Z-scores they do contain some theoretical beauty.

Woof appears to be the only one besides me who realises that Z-scores CAN be used to calculate the probability that A beats B. If A and B are Normal, then so is "A-B", the distribution of every possible matchup of A vs B.

Trouble is I believe it's highly unlikely in typically chaotic races that ratings are Normal.

Hi there, I gave an example of A vs B, but this isn't the method I employ, an idea is to use your database to find the avg winner score per Class of race, then find the avg Stdevep of each winner in each Class. This will provide you with the avg score each winner needs to acheive in each Class. Then instead of using B when calculating A z-score your substitute it for your claculated avg winner score.