Quote:
Originally Posted by Ted Craven
J,
Sartin's thesis was/is: speed = energy = class. And some would say that using adjusted Total Energy (TE) alone (though I use the corollary of Perceptor/Primary Line Score) you get a Win % in the golden ratio range (~62%) from the top 3 and that this is sufficient measure of 'class' to nudge you towards breakeven or positive ROI.
Perhaps the 'cheap speed' you observed could be discounted by other means - are you able to cite an example (e.g. from the Demo Database?) Of course, single instances will always occur, and sometimes 'local knowledge' does the trick (ask me how I know to discount Ft. Erie speedballs at Woodbine  ). But this is a reason I urge caution using CR (APV, consistency) as a measure of 'class'. Sartin had dropped CR/APV after the mid-1990s for much the same reasons I'm urging caution - it suppressed more obscure horses with 'actual class' represented by energy measures and disbursement relative to today's competition. I reintroduced it as much as a measure of 'back class' or a rationale to seek a line further back, as anything else.
On re-reading your original post, I think you may be asking if one risks much (or have studies been done) by eliminating from Win the bottom half (or so) of the CR/APV range. Interesting study, now that I think of it. Compound that with Total Energy or the VDC rank and you could perhaps be on to something.
Perhaps the closest I can come to advice re the keeping/eliminating horses based on CR, is when considering eliminating a 6th ranked horse relatively tied on other counts with a 5th ranked horse, I'd err on the side of CR. Or, horse has high TE, high CR but layed off 180+ days (non-Stakes): I'll move it out of the Win slot but consider keeping for ITM. Or, the high TE and high CR rating comes from a few months ago and I'm trying to decide if I should go back those 4 lines. Something like that.
Examples might help.
Ted |
Distinguishing contenders and non-contenders using APV/CR when those entries rate high on TE depends on the values used in CR. The CR I developed for my own use in the 1980s (and gave to Dr. Sartin and anyone else who wanted it) was (to the best of my knowledge) the first realistic compounding of values because it was tiered by race class.
Basically, APV + ITM is a tweaked APV--the values are very heavily weighted toward APV. Because APV is often artificially inflated by state-bred races and other anomalies, it tends to overshadow otherwise significant differences in ITM values. The CR I used combined APV + ITM% + Win% + EPS as a value appropriate to the class level of the race. For minor tracks, the increments of EPS might be $500, while the same value might be increments of $1000 to as much as $5000 at higher grade tracks. The whole idea was to make the EPS an "equivalent" (in magnitude) value for compounding.
As you know, one of the most misleading outputs is APV calculations on lightly-raced entries. To avoid the "division by zero" error in the old DOS programs, if there were no wins, a show or place would be moved to the win position to avoid the error in calculation. That seems to have become so accepted that no one questions why it is done, or what effect it has on the APV calculations (and database records of APVs).
After that regretably long-winded prelude, the short answer is that a CR can be very useful in recognizing "cheap speed"--an entry with high TE from a lower grade race, entered today at a higher grade in which it is unlikely to "run to its numbers." One of the most stunning insights about wagering is that every losing bet you don't make is the equivalent of picking 50% winners at even money.
Thanks