Longevity of a PRI Score

The Longevity of a PRI Score

A PRI score will change with time, but what is the longevity of a PRI score? Any process that involves statistical methods is only as good as the information in a data base. This particularly true when the data is continually changing. Any method using a data base must be robust enough to accommodate these changes. A data base which involves racehorses is continually changing. Just consider the AEI (Average Earning Index). Every run a horse has will change its AEI value. Similarly, every time a horse wins a Stakes Race, the pedigree compatibility factors will also change. The change will be almost imperceptible for a cross such as Northern Dancer x Mr Prospector. But what about the lesser lights?

Up Dated Results

To test the robustness my analysis system I re-examined the data entered in my first post of 2.5 years ago (Yearling Prices and Racing Ability: the rewards are hard to find). The updated results are given in the table below:

*PRI Score measured Feb 2019

**PRI Score measured Aug 2012

***PRI Band/Medium AEI is from Flavone Private data base. For example, Honesty Prevails with a PRI score of 93.8 lies in the data base band of PRI scores 95-90 which have a medium AEI value of $110k.


Firstly, as a prelude I need to state that the examination of seven horses is hardly statistically significant, but my conclusions are backed up by a considerable amount of data I have accumulated in over 20 years researching the subject. Secondly, breeding and/or finding good horses is an inexact science with a bit of art thrown in. For example, within PRI bands there is considerable variation in AEI values. However, I would predict that more likely than not the AEI figure is close to what you would expect from a horse with PRI values within that band.

  1. The PRI values measured for these horses in 2019 have not changed dramatically from those measured in 2021. The longevity of a PRI score held up well.
  2. In their racing career all these horses failed to return anywhere near their purchase price.
  3. The link between PRI score and AEI is reasonable for these seven horses. What was predicted is reasonably close to what was achieved.
  4. A phone call to me in 2019 would have saved some people a lot of money!