Hi pezmaz and dave jay,<br>I don’t know the full answer to your question but years ago I bought a computer program to analyse horse races.<br>This needed the input of a speed figure and the weight each horse was allotted as well as going and distance of a race.
This program said Topspeed figures are already adjusted for weight, so that the weight for all horses even in handicaps should be taken as 12 stone for jumps and 9 stone for the flat.<br>Going and distance still had to be input as a separate value.<br>Cheers :)
Topspeed figures are adjusted for weight when they appear against the race card. Dave Edwards does this now and is one of the best. Earlier Topspeeds did not have much of a clue and made arbitrary adjustments. Some do not allow lightly weighted horses to have the full mathematical benefit as reducing weight to extremes does not make horses run any faster, just make it easier to run at the same speed as before.
In USA, unscientific dimwits like Andy Beyer try to adjust speed ratings for different distances and track biases, even for changes from dirt to turf etc. This is maybe where you read this. You can always get different numbers using mumbo jumbo but they do not mean anything at all. The trick if you want to avoid the poorhouse is to only apply speedratings for the same distance, going and course type as previously earned, if they are to have any predictive effect.
To Pezmaz the book that most likely fits your description is Racing Systems With The Pocket Calculator by John White – Foulsham press 2001. This gives rather exhaustive details on balancing out topspeed and postmark ratings together with distance and gong plus many more points of interest hope it helps…