Understanding the Ratings - Perfect Match and 20/20 Match

G1 Goldmine rates a pedigree by comparing it against the pedigrees of horses that have already reached stakes level. Rather than a score that moves up and down, the result is one of three fixed bands, so the same pedigree reads the same way each time you look at it.

The three bands

1. Perfect Match: The pedigree qualifies as a 20/20 Match and, in addition, at least two stakes winners share a matching ancestor in every quarter of the pedigree.
2. 20/20 Match: Two or more Graded Stakes winners share more than 20 ancestors with the pedigree within five generations.
3. No Match/Blank/Normal Match: Neither condition is met. The pedigree has limited proven success behind it.

How a 20/20 Match is determined

Every stakes winner that Stallion Match returns is compared with your pedigree across five generations. The Similarity Score (CSI) shows how many ancestors that stakes winner shares with your mating, as a percentage and a count out of 31. For example, 68%(21) means 21 shared ancestors.

A mating is a 20/20 Match when two or more Graded Stakes winners share more than 20 ancestors with it. More than 20 out of 31 is about 65%, so you may also see the same test described as a Similarity Score of 65% or higher. The two descriptions mean the same thing: one counts the shared ancestors and the other shows them as a percentage.

Shared ancestors also need to sit at a similar depth in both pedigrees. Two pedigrees can carry the same ancestor in very different positions, and that is a weaker relationship than the same ancestor appearing at a similar depth in both.

How a Perfect Match is determined

A Perfect Match is a 20/20 Match that also passes a distribution test.

The pedigree must first meet every 20/20 condition. Then, at least two stakes winners must share a matching ancestor in each quarter of the pedigree.

That second requirement is demanding. It means the resemblance runs through the whole pedigree rather than being concentrated in one corner, and that more than one stakes winner independently shows it. A pedigree can carry a strong sire-side resemblance and still fall short of Perfect Match if the bottom half contributes nothing.

Every ancestor counts, male and female

The algorithm considers every ancestor within the first five generations, female as well as male.

This matters because a pedigree's influence does not arrive only through sires. Analysis restricted to the male line leaves most of the pedigree unexamined, and the female side is where family consistency and much of the classic influence sits. Including both produces a fuller comparison against the global stakes winner list.

How often the patterns appear

The bands were tested against a control group to establish whether they separate proven performers from horses that did not perform.

• 24% of stakes winners carry a Perfect Match rating.
• 3% of underperforming horses carry a Perfect Match rating.

The underperforming group was defined as horses in Australia since 2021 with multiple starts, no wins, and prize money under $3,000.

Two points are worth being precise about when reading those figures.

The comparison group is the bottom of the population, not the average horse. The study establishes that the pattern separates stakes winners from demonstrable non-performers, which is a specific and meaningful result.

The figures describe how often the pattern appears in each group. They do not mean that a pedigree carrying a Perfect Match is eight times more likely to produce a stakes winner. That is a different claim and it is not what the data shows.

Where the ratings appear

Ratings are returned by Stallion Match and shown alongside the similar stakes winners your search returns.

Clicking any stakes winner in that list opens the side-by-side pedigree comparison, which shades the matching ancestors so you can see exactly which positions matched. A rating tells you a resemblance exists. The comparison shows you what it consists of, and whether it runs through the parts of the pedigree you care about.

For the difference between the two match measures behind the rating, see Exact Score vs Similar Score.

How to use a rating

A rating is a starting point, not a conclusion. It compresses a large amount of comparison into a single label so that a long list of possible matings can be sorted quickly.

It says nothing about the individual mare's suitability, the physical match between the two horses, the stallion's fee against your budget, or the programme you intend to race the foal in. Use the rating to narrow a roster to a shortlist, then use the Impact Profile to assess the individual crosses within each pedigree.

Related articles

• Stallion Match explained
• Exact Score vs Similar Score
• Impact Profile explained

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Countries Included: AUS, USA, IRE, GBR, FRA