What's a No Rating?
Written by Alan Porter 1 | Jun 17, 2010 |
We are often asked why we assign a No Rating designation to some crosses. Well, it's quite simply that sometimes the most honest answer to a question is “We don't know – there isn’t enough evidence to give a verdict."
Click for Conveyance's pedigree, an example of a No Rating.
In assessing a cross, the TrueNicks algorithm tries to calculate a rating on the basis of the minimum possible number of generations from the foal (or hypothetical foal). If there is not enough evidence to calculate a score on nearer generations, the program will go back as far as the grandsire of the sire and the grandsire of the broodmare sire, and perhaps a little surprisingly, we have found that there is very little drop off in accuracy in the scores calculated at these more distant removes. This being said, we also felt that the required degree of accuracy could not be maintained if the scope of the cross was extended another generation, to where the selected ancestors would be 4 x 4 or 4 x 5.
A result of this decision is that there is sometimes insufficient evidence to rate many crosses for younger, emerging sire lines. Take for example two recent classic winners: Kentucky Derby (gr. I) hero Super Saver and last year's Belmont Stakes (gr. I) victor Summer Bird (TrueNicks). Super Saver is by Maria's Mon, by Wavering Monarch, and Summer Bird by Birdstone (TrueNicks,SRO), by Grindstone. Both sire lines are almost “one horse sire lines,” meaning that other than the horses themselves, there are very few other effective branches (although Maria's Mon's son Monarchos has sired a number of stakes winners).
By way of contrast, consider Eskendereya (TrueNicks,SRO), who would have started favorite for the Kentucky Derby. He is by Giant's Causeway (TrueNicks,SRO) (who already has two stakes-siring sons in Shamardal (TrueNicks,SRO) and Footstepsinthesand), who is in turn, a son of Storm Cat. In the case of Eskendereya, the broad Storm Cat line has sufficient starters and/or stakes winners with the most commonly found commercial sire lines to allow a rating to be calculated. Giant's Causeway alone has 877 starters and 80 stakes winners. As an inevitable consequence, Eskendereya is going to return more ratings - both high and low - with a cross section of mares than will Super Saver or Summer Bird.
However, even with a No Rating, a TrueNicks page can often offer useful information. For example, the best five horses on the cross will sometimes reveal a cross that has produced a good stakes winner from the sire line with very limited opportunities. The TrueNicks page also reveals inbreeding and line breeding that might be a potential positive, as well as the dosage profile, which can be a clue to aptitude.
It's also possible to look at a No Rating as an opportunity. If a sire line has few distinct preferences, new stallions of this line may be open to options that have yet to prove themselves with the sire. Here, inbreeding patterns, preferences of the broodmare sire, and the female line are worth considering. Following the emerging runners listed in the best five horses on the cross may help breeders stay ahead of the curve, perhaps identifying an effective cross before it is proven statistically.