Ventura GeoScore (VGS) Explained
The Ventura GeoScore, usually shortened to VGS, measures the strength of a cross between two ancestors by comparing how many Group 1 winners that cross actually produced against how many it should have produced.
It is an opportunity-adjusted measure. A cross that has been tried thousands of times is expected to produce more Group 1 winners than one tried a hundred times, and VGS accounts for that before judging it.
The baseline
VGS is centred on 1.00.
- 1.00 means the cross produced exactly as many Group 1 winners as predicted. This is the baseline for all scores.
- Above 1.00 means the cross outperformed opportunity.
- Below 1.00 means it underperformed opportunity.
The calculation is straightforward once the prediction exists:
VGS = actual stakes winners divided by predicted stakes winners.
How the prediction is built
The prediction is derived country by country, because racing populations differ and a cross should be judged against the pool it was actually operating in.
For each country, the analysis establishes how many stakes winners were born there in total, then what share of those carried the sire in question and what share carried the dam in question. Combining those two shares gives the number of stakes winners the cross would be expected to produce in that country if the two influences were simply meeting at their normal rates.
The actual number is then set against that expectation.
Regional scores and the worldwide score
Two levels are reported.
Regional scores give an individual figure for a particular country. Use these when you are breeding for a specific programme, since a cross can perform very differently across jurisdictions.
The Ventura GeoScore is based on the cross's worldwide performance, and is therefore built on the largest available body of relevant data. Use this when you want the most statistically robust read rather than the most locally relevant one.
Where the two diverge sharply, that divergence is itself informative. A cross scoring well worldwide but poorly in your country is worth understanding before you rely on it.
When VGS is available
VGS only applies where crosses have been specified on both the top and bottom halves of the pedigree in the search panel. The score measures the interaction between a sire-side influence and a dam-side influence, so it cannot be computed from one side alone.
If no score appears, this is usually the reason.
How to read it
Distance from 1.00 is the signal. A score of 1.05 is close to expectation and says very little. A score well above or below is where the information is.
Check the counts underneath. A ratio built on two actual Group 1 winners against one predicted produces a VGS of 2.00, which looks outstanding and rests on almost nothing. The underlying numbers are shown alongside the score and should be read with it.
Group 1 winners are rare. Because the measure works at the highest level only, the numbers involved are small even for well-used crosses. VGS is more volatile than measures built on all stakes winners, and should be treated accordingly.
It measures two ancestors, not a pedigree. Like nicking, VGS assesses one interaction. The Impact Profile assesses 20 crosses across a pedigree, and the two answer different questions.
Where it fits
VGS appears in Pedigree Search results alongside the strike rate, the Affinity Matrix and the Aptitude Profile.
Read against the strike rate it is particularly useful, because the two are asking related questions differently. Strike rate reports a raw proportion. VGS reports performance relative to expectation. A cross can have a modest strike rate and a strong VGS if it has been achieving results with limited opportunity, and that combination is often more interesting than a high strike rate built on heavy use.