A Critical Look at Nicking

“The mythology surrounding the breeding of Thoroughbreds is pervasive. A few of

these myths are the astonishing stupidity of the dosage system, the absurd overemphasis on the female family, and the irrational belief in the validity of nicks.”

- John R. Gaines, founder of Gainesway Farm and The Breeders Cup

Few breeding theories have permeated the psyche of the American breeder more than nicking. Nicking pundits have turned this phenomenon into a financial windfall, and more importantly, a concrete paradigm that has effectively shielded itself from critical review. Yearling buyers are not immune from this trend either, forcing many breeders to check the nick ‘rating’ as they plan their commercial matings each year. It has become a self-perpetuating cycle that shows no signs of slowing down.

While we are not willing to discard the underlying theory altogether, the current methodologies used to create the nicking craze certainly deserve a thorough and critical look. Most will look to nicking’s close relationship with the computer and lend it credibility without applying any type of critical analysis that may uncover the flaws, limitations, and possibly, the usefulness of nicking.

As always, we should begin with some basic understanding of nicking. Citing one of the leading proponents of nicking theory:

“… nick ratings are based on the percentage by which a certain sire line, when combined with a certain broodmare sire line, exceeds its performance, on average, with other lines. To make the rating easier to understand, we have developed a scale which converts the percentage to a letter grade ranging from "F" to "A". In rare cases, the rating may be as high as "A+" or even "A++". We emphasize that an "A" rated nick does not guarantee success, nor does an "F" rated nick guarantee failure.”

Though the author goes on to elaborate on the intricacies of nicking theory, the basic premise is well spelled out here. In short, the probability of a hypothetical mating becoming successful is calculated by examining the history of crossing a particular sire line with a certain broodmare sire line.

Before tackling the shortcomings of nicking theory, we should start by mentioning the usefulness of nicks. The best description I’ve ever heard for the application of nicks is that of a ‘tiebreaker’. In other words, with all other variables being equal i.e. race record, conformation, etc, the astute breeder will use nicking theory as a means of tipping the scales. After all, if your mare’s sire line has historically faired better with one sire line, and horrifically with another, it may be prudent to select a representative from the former rather than the latter, after all other factors have been thoroughly examined and found to be equal.

Unfortunately, the rationale and methodologies behind nicking have many fundamental flaws and limitations. As we see it, a brief look at each problem area:

Insufficient Sample Size

Even the most introductory statistic courses stress the importance of sample size and the pitfalls of drawing conclusions based on limited evidence. Time and time again, I’ve heard clients remark about the strength of a nick based on two or three starters. Even more astonishing, I often hear of the anecdotal nick where a breeder is convinced of a magical affinity between sire lines based on one runner.

Take for example, the alleged nick between daughters of Lyphard with A.P. Indy and his sons. Assigned a letter grade of B+, a breeder with a daughter of Lyphard may be quick to assume that the rating’s purveyor went to elaborate lengths to come up with such a neatly-packaged indicator. The truth is, daughters of Lyphard have only produced seven starters from A.P. Indy and/or his sons. To make a broad-reaching inference based on just seven starters is an enormous leap of statistical faith.

Omission of the Female Influence

Perhaps the most obvious flaw in nicking theory is the omission of the female influence. If nicking pundits are able to point to certain statistical probabilities based on the sire line, they should be able to point to similar probabilities based on certain female families and blue hen type mares.

Imagine a five generation pedigree. In cases where the nick rating is based on a paternal influence 3 generations removed and a maternal influence 3 generations removed, the final rating fails to incorporate over two-thirds of the entire pedigree. No theory out there can claim to take 100% of all factors into consideration, but nicking theory falls well short of being an inclusive theory.

Lack of Replication in Lower Percentiles

Nicking theorists are often quick to point out how their theory applies to the upper levels of horse racing i.e. unrestricted and graded stakes winners, but they never mention whether or not the same phenomenon exists in the lower percentiles of racing. After all, if this were the case, and we saw the same dispersal of nick ratings in the bottom tiers, the theory would have no practical use. John Gaines saw this and commissioned his own study of lower level claimers to see if they paralleled the populations used by nicking pundits:

“The big issue is, that while there are all of these statistics, these pedigree nerds, the people that are promulgating all of this scientific nonsense, there is never any control group. It is all selective, self-serving, worked-over information. I did a study one time with Dewey Steele about nicks, and we found the worst horses, those finishing last at Thistledown and Charles Town, had the same nicks as the horses that were winning the classics. One of the dumbest things that's done is that they take an infinitesimal sample of maybe three or four or five horses and pompously say that is a nick. From my scientific point of view, a sample that is that minuscule is worthless.”

Failure to Distinguish Generations Removed

A handful of stallion farms in central Kentucky now allow prospective clients to obtain nick ratings for hypothetical matings to their stallions. This may have been a mistake on the part of the nicking company as breeders are now able to compare and contrast how the ratings change as a function of different variables. Even the layperson will notice irregularities that don’t adhere to scientific principles.

As we began to tinker with a few of these sites, one thing stood out immediately: the rating did not change as a function of the number of generations a certain sire was removed from the hypothetical foal. For example, if you wanted to see how your daughter of Afleet nicked with the influence of A.P. Indy, the rating would remain the same if you’re breeding directly to A.P. Indy or to one of his sons. Common sense tells us that our expectations should not be identical for a direct mating with A.P. Indy versus a mating with Stephen Got Even. Yet, nicking theory in its current format fails to distinguish the difference.

Failure to Isolate Variables

No breeding theory should be expected to isolate a variable (in this case, racing aptitude) entirely. It simply isn’t possible. But in the case of nicking theory, it does little to isolate the racing aptitude variable to an acceptable, statistically significant degree. Consider the following variables that are not accounted for by nicking theorists:

conformation strength/weaknesses
race record of the sire and/or dam
affinity for sire’s found beyond the 2nd dam
role of the sire’s broodmare sire
racing styles of the sire and dam
soundness issues that may have impact ratings
distance capacities within the immediate family
affinity for dirt vs. turf

None of these variables are taken into account when the nicking pundit’s computers spit out a rating, nor is the client asked ahead of time what racing aptitudes he is aiming for with a particular mating.

“Answer-Oriented”

With such concise descriptions as A+ or B-, the whole concept of nicking is geared primarily for providing simple, easy-to-understand answers that do little to reveal methodologies or the complexities of planning a successful mating. This certainly works to the benefit of those with a financial stake in nicking, as it is always more efficient and profitable to sell a simple, neatly-packaged concept as opposed to selling a complex methodology that requires more of an explanation.

The main problem here is that we’re dealing with a very dynamic question: What is involved in a successful mating? Nicking theory tries to answer this question with an all to simple letter grade, which is terribly insufficient to answer such a complex question.

Less Research by Mare Owners

An indirect result of the nicking craze is the effect it has on the behavior of mare owners. Too many breeders (and yearling buyers for that matter) are allowing this over-simplified method of planning matings to take up the bulk of their planning process. Many will simply make a phone call to get the latest ratings before booking their mares. Less and less time is being spent on researching progeny results, conformation, market trends, etc. Where as this should be viewed as a tie-breaker at best, it is all too often being used as a starting and ending point.

Again, we are not ready to discard the entire theory. In situations where the methodology is revealed to have sufficient evidence by way of sample size, variables are being isolated to some extent, and it is used more along the lines of tipping the scale, nicking may have some occasional practicality. In all other scenarios, mare owners need to tread lightly and understand that nicking is not a short-cut to doing the relevant research.