• Breaking Down the Brisnet Prime Power Rating

    POSTED Jun 19, 2014
    It’s no secret that, for many moons now, I have been trying to beat the game with mechanical methods of play. In large part, because I simply don’t have time to handicap like I did 5-6 years ago… nor do I enjoy the process like I used to.

    It is also no secret that I have been largely unsuccessful in this endeavor. 

    Don’t get me wrong: I’ve found some great systems and angles — ones that, through testing, I am confident will continue to offer solid ROIs for months and years to come. But, alas, they all suffer from “Tony Romo Disease” — they don’t show up often enough to produce consistent, meaningful returns.

    Still, I love the idea of a mechanical method that can, at the very least, help guide one’s wagering decisions. So, with that in mind, I decided to slice and dice the Brisnet Prime Power Rating and see if I could find any helpful wagering angles.


    (Click on image to enlarge)

    First, using a database of random races run from July 2012 to February 2013 at racetracks across the country, I examined the horse with the top (highest) Prime Power rating in the field. (In the Brisnet Ultimate Past Performances, the Prime Power rating and field rank is found right before the horse’s lifetime record — see California Chrome above.)

    Number: 11,953
    Winners: 3,972
    Win Rate: 33.2%
    $2 Return:  $1.75
    ROI: -15.09%
    IV: 2.48

    Not bad. These numbers are similar to what one would expect from the post-time favorite, which gives us a good starting point. Now let’s see what happens when the top Prime Power horse goes to post as a morning-line overlay (odds greater than or equal to the morning line) or a morning-line underlay (odds less than the morning line):

    OVERLAYS

    Number: 2,186
    Winners: 428
    Win Rate: 19.6%
    $2 Return:  $1.64
    ROI: -17.81%
    IV: 1.49

    UNDERLAYS

    Number: 9,767
    Winners: 3,544
    Win Rate: 36.3%
    $2 Return:  $1.71
    ROI: -14.48%
    IV: 2.70

    While these numbers may surprise some readers, who assume that higher prices naturally mean higher profits, they are, I have found, very indicative of what happens when one looks for overlay opportunities with “obvious” contenders.

    Caveat emptor applies at the racetrack too.

    A horse that looks like a legitimate 2-1 shot does not necessarily offer “value” at 20-1. Rather than rushing to the window to empty one’s 401(k) on such horses, players should ask themselves a simple question: Why? Why is a horse with so many positive attributes (remember, the Prime Power rating is a comprehensive assessment of ability) being dismissed in the wagering? What is the crowd considering that the Prime Power rating is not?

    Granted, some of these horses are, in fact, genuinely overlooked. I’ve witnessed numerous animals that I thought were fairly-priced at 2-1 or less pay double digits — but that is the exception, not the rule.

    With this in mind, it should come as no surprise that horses with the top Prime Power rating in a race actually perform better when that rating is lower, rather than higher:

    * Top prime power rating of 100 or greater.

    Number: 11,294
    Winners: 3,752
    Win Rate: 33.2%
    $2 Return:  $1.69
    ROI: -15.36%
    IV: 2.49

    * Top prime power rating of less than 100.

    Number: 659
    Winners: 220
    Win Rate: 33.4%
    $2 Return:  $1.79
    ROI: -10.55%
    IV: 2.42

    Moreover, horses with the top Prime Power rating that finished poorly last time out (fifth or worse) return a profit — further proof that factors esteemed by the public, i.e. a good last race, are best avoided when looking for overlays:

    * Top prime power rating of less than 100.
    * Finished fifth or worse in last race.

    Number: 225
    Winners: 74
    Win Rate: 32.9%
    $2 Return:  $2.03
    ROI: +1.69%
    IV: 2.36

    Of course, there is nothing to say that these numbers will continue to hold, but I hope they illustrate both the pros and cons of a mechanical approach.

    On the plus side, using the Brisnet Prime Power rating is quick and easy and, in some instances, profitable. On the negative side, all mechanical approaches suffer from one major drawback: they can only measure what was… not what is or what will be.

    Nonetheless, handicappers willing to put in the time to validate or invalidate a mechanical rating might very well profit from the experience.

    (Click on image to enlarge)
    NOTE: Rue Saint Honore had a race-best 95.6 Prime Power rating and finished 7th in her last race on July 29, 2012.
  • 5 comments:

    Unknown said...

    This cool, thanks for sharing. Are these test limited to just dirt races? The score rate is supposed to go up to 60% when the difference is greater than 10 points in prime power.

    Derek Simon said...

    It's for all races. Horses with a 10-point Prime Power advantage recorded the following stats:

    Number: 744
    Winners: 380
    Win Rate: 51.1%
    $2 Net Return: $1.80
    ROI: -9.97%

    Derek Simon said...

    Coming back within a month only marginally improved the stats, BTW.

    TOP BRISNET PRIME POWER RATING

    Number: 8,490
    Winners: 2,867
    Win Rate: 33.8%
    $2 Net Return: $1.73
    ROI: -13.46%

    Anonymous said...

    Do you have any queries between the Prime Power and the odds the horses went off, or Prime Power and their beaten lengths?

    For example, in the 10 point advantage Prime Power horses my guess is the average beaten lengths is 0 and odds are less than 1/1.

    What about horses within 2 points of the Prime Power? What do they average in odds, and beaten lengths? If one could get a relationship on this one could structure a fairly effective oddsline.

    Rob S said...

    How were you able to test these ideas/angles? Does Brisnet have some kind of software to backtest ideas or angles?

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