Saturday, May 31, 2008

First Report Complete

If you don't want to read any shameless self promotion, feel free to skip this blog entry. That said, my first full research report is complete and available for purchase. It compares the racing results of horses purchased at two year old auctions (specifically Fasig-Tipton Selected Two Year Olds in Training at Calder) with the results of those purchased at yearling auctions (Fasig-Tipton Selected Yearlings at Saratoga). The results are a real eye-opener...if you're spending money at the wrong type of auction for the price range of horse you're buying, you're potentially wasting a lot of money, and could achieve much better results in the long run by limiting yourself to the right type of auction. I'll be putting some information about the study up on my business site ThoroughMetrics in the next few days, but for now, if you'd like to learn more about the study, send me an email at

Sometime in the next few days, I'll start on my next study. I'm tentatively planning to look at which is a better predictor of success for the offspring of a mare...the mare's racing ability, or the success of her previous offspring. I haven't thought through all the details yet, but I picture the following high level steps:
1. Get a fairly random list of horses foaled in the same year.
2. For each horse, record some measure of their racing success (probably SSI), sire, sire's stud fee in year conceived, dam, dam's SSI, # of previous foals for dam, median SSI of dam's previous children, and mean SSI of dam's previous children.
3. Calculate correlations between horse's SSI and dam's SSI, horse's SSI and dam's median offspring SSI, and dam's mean offspring SSI.
4. Divide horses into tiers based on stallion's stud fee and dam's SSI/dam's median offspring SSI/dam's mean offspring SSI and compare horses' SSI in each category. This should control for the fact that dam's of one 'type' (good racer, good breeder) may tend to be sent to better stallions.

The thing that makes this interesting to me (other than the possibly utility of the results) is that there's a tradeoff here. The success of a dam's previous offspring is obviously a more direct measure of what we're looking for - the ability to pass on racing ability to children. However, it's also something that has VERY high variance. So many great racehorses have had half (and full) siblings who were duds on the track. The success of a mare during her racing career is a much more indirect measure of what we're looking for...but it's also much lower variance. Despite the equally small sample size, the results of a horse's races are much more consistent than the performance of their children.

If I had to guess, I'd expect the racing ability to have slightly more influence the the success of previous offspring. But the beauty of statistical research is that I don't have to guess...I can actually measure it.

I'd love to hear people's thoughts on the it a useful study? Are there any obvious flaws in the high level study design that I've described?

1 comment:

Winston said...

Doesn't the AEI/CI of the sire take some of this into account. Also, Estes performed his studies and came up with the answer that the single most predictive quality in a broodmare was her racing ability.
He published extensively and maybe you can find his work to start from.
You also might have something else in mind but it all sounds great.