cosmicsports
Colt
Yes use all times not just winners(remember to use the corrected times adjusted for the weight and the track variant as already discussed how to do this)
15th percentile down the ladder
why 15th …just experience tells me this is as good as any….no correct answer….the median I believe would include too many slow times, 15th is a sensible representation and cuts out ant outliers at the top
I thought you just wanted to line up the times, if you are attempting to create usable ratings to adjust for future races, then it’s very difficult to give full advice…I don’t have the data you have.
Im guessing we are dealing with a country I know nothing of with just one racetrack, I don’t know where you obtain your track variant, the track variant could be useless. Creating an accurate track variant is essential.
In a days results if the track variant is 2,30 seconds is this the same variant for 6 furlong races and 7 furlong races, if so that makes no sense.
Does your data contain official ratings for the horses or any indication of class of runners in each race.
When you find out that a horse has run a corrected time of 1.13.5 and your standard is 1.14
You know this horse is 1/12 sec/furlong fast. You need to multiply this by a constant that will give your horse a rating that will then line up with kg so you can adjust for future weights in future races.
Again there is no correct answer…for U.K. I ended up with a constant of 126 to convert to a pounds friendly scale.
I would suggest you use 58 as the constant.
so in our example the horse is 1/12 sec/fur fast so 1/12 x 58 so the horse is 4.83 kg fast
So we could call this horse 104.83 speed rating
Do this for every horse, then adjust for kg carried in future races
The track variant will be vital, it will be a case of if your variant is accurate your ratings will be accurate.
Well, I suppose it's got to be the same everywhere.
Most of our horses are from UK, some are bred in Greece and a few French.
But as I said different types of surface may produce different effects (dirt-grass-artificial). Ours is dirt.
The track variant is a long story.
The best track variant is the one that finds most winners really, in the sense that we use the recent time figures only to predict the
winner of a race and forget all other things we usually take into account (such as jockey, early speed, days off ...).
I tried without any track variant and certain poor results obtained.
Then I tried to work out class par times. Better but not quite.
The one they publish in our press is the one doing better.
This is not the same for all distances of course and I don't know the precise method. It's a method used by DRF in the States I 'm
told (or adapted from it) but at this time I don't know more.
So let's accept that now (despite some grumbles I hear from other people).
The issue here is to compute the weight effect, just that.
I never use ratings. To compute probabilities I use raw times and also Hill's integral:
There are some ratings BHA produced for us. I don't fancy them a lot. It helps the jockey club to group horses better than before
but I don't fancy.
I 'm trying out something now along the lines you suggest. I will return after a while