Strike Rate
Strike rate is the most quoted number in stallion advertising and one of the most frequently misread. It is a simple ratio, but the answer it gives depends entirely on what you divide by, and two stallions quoted at the same strike rate can be telling you very different things.
The basic calculation
Strike rate expresses successful performers as a percentage of opportunity. In its most common form:
Stakes winners divided by runners, multiplied by 100.
A stallion with 200 runners who has produced 12 stakes winners has a stakes winners to runners strike rate of 6 per cent. The same logic applies to a family, a cross or any other group of horses you can define.
The purpose of the ratio is to strip out volume. A stallion covering 200 mares a year will produce more stakes winners in raw numbers than one covering 40, simply through opportunity. Strike rate asks a fairer question: of the horses he actually got, what proportion reached stakes level?
The denominator changes everything
This is where most misreadings happen. "Strike rate" can be quoted against several different denominators, and they are not interchangeable.
- Against foals. Every foal born, including those that never reach the track through injury, illness or failing to make a racehorse. This is the harshest denominator and produces the lowest figure.
- Against runners. Only horses that actually started in a race. This is the most commonly used, and the one to assume unless told otherwise.
- Against winners. Stakes winners as a proportion of horses that won any race at all. This flatters the figure considerably, because the weakest horses have already been excluded from the denominator.
A stallion quoted at "12 per cent stakes winners" against winners and one quoted at 12 per cent against foals are not comparable, and the gap between them can be large. When a figure is quoted without its denominator, treat it as marketing rather than analysis.
Sample size, and the first-season problem
Percentages are unstable when the numbers behind them are small. A first-season sire with 30 runners and 3 stakes winners has a 10 per cent strike rate, which reads as outstanding. Two more seasons of runners may confirm it or halve it.
The same distortion applies in the other direction. A stallion whose first crop happens to miss can look ordinary on a strike rate that will correct itself as volume builds.
The practical guide is to look at the raw counts alongside the percentage, and to be sceptical of any strike rate calculated on a small crop. A stallion's first crop reaching racing age is the first real test of him, not the final verdict.
What strike rate does not tell you
Mare quality. This is the largest confound. A stallion standing at a high fee is sent better mares, and better mares produce more stakes winners regardless of the sire. Part of any strong strike rate reflects the quality of the book rather than the transmitting ability of the stallion. This is why a young stallion's figures often fall as he moves from a well-supported first book to a less fashionable one, and why a stallion who performs well on modest mares is genuinely notable.
The level of the black type. Strike rate counts stakes winners without weighting them. A stallion with several Group 1 winners and one with the same number of Listed winners can show identical figures. Depth of quality is invisible in the ratio.
Where the racing happened. Stakes races are not equally hard to win everywhere. A strike rate built in a deep, competitive jurisdiction is a different achievement to the same figure built in a shallower one.
Consistency. Two stallions with the same strike rate may distribute it very differently, one producing steadily across every crop, the other carried by a single exceptional year.
Strike rate for crosses and families
The same ratio is used beyond individual stallions. A cross between two ancestral influences has a strike rate: of all the horses carrying that combination, what proportion reached stakes level? So does a female family.
This is closer to how G1 Goldmine uses the figure. When you run a search on a pedigree pattern, the platform reports the strike rate for the searched cross, giving you the proportion of runners carrying that pattern which produced stakes winners. That is a more useful question for a breeder than any single stallion's headline number, because it speaks to the mating you are actually considering rather than to the sire in isolation.
The Impact Profile extends this across a whole pedigree, assessing crosses individually and showing which of them have produced stakes winners and at what rate, rather than reducing a pedigree to one figure.
How to use it well
Treat strike rate as one input, not a verdict. Ask what the denominator was, how many runners sit behind the percentage, what class of black type it represents, and what quality of mares produced it. A figure that survives those four questions is worth paying attention to.