2007 Kentucky Derby Preview:

Note: The first section of this article is the standard introduction to our pace-based approach to analyzing the Kentucky Derby.  Those familiar with the methodology may wish to either review it or proceed directly to this year's analysis here. 

It is often said, “pace makes the race”.  We are all familiar with the phrase, but I dare say few of us have a firm grasp on what it means in a practical sense.  The folks at Trackmaster define pace as the tempo or rhythm of a race, which is as good a definition as any.  They further suggest, “pace is important primarily as it effects the overall energy pattern of a race horse”.  Accepting that description creates opportunities for measurement and quantification.  In other words, if a horse’s energy pattern, perhaps better described as its energy distribution throughout the course of a race, is critical to the race’s outcome, then measuring that energy distribution could provide significant insight into the details of the horse’s performance.  Once we understand the subtleties of how a horse typically or better yet, most efficiently, distributes its energy in a race we can hopefully apply our understanding to the demands of another race.  This is an approach we have used for several years to assess the potential of Kentucky Derby contenders.  By analyzing the pace characteristics of the Derby starters in their prep races, we can compare the results to those found for previous Derby winners in their prep races.  Some will fit the successful historical patterns while others won’t.  

Our methodology is multifaceted.  First, we use linear regression (involving fractional times and lengths behind) to generate the slope and intercept of the best straight line that models the individual performance.  Slope is a measure of fatigue.  The higher the slope, the longer the time required to negotiate an additional distance.  Slopes will generally fall between 0.9 (slow early-fast late) and 1.2 (fast early-slow late). Intercept is a measure of early speed and is inversely related to the slope.  In this case, the lower the intercept, the greater the relative early speed.  Intercepts also will usually fall between 0.9 (fast early) and 1.2 (slow early). Correlation Coefficient is a measure of how efficiently a horse's speed is expressed throughout the whole race.  Perfect efficiency is equal to a Correlation Coefficient of 1.00000.  Any value below 1.00000 represents less than ideal efficiency, although it is almost always greater than 0.99900.  The very best horses continually display Correlation Coefficients above 0.99990 while lower quality horses may not display Correlation Coefficients that high. We can subsequently use the slope and the intercept for a race to calculate a predicted time at any distance.  These times include a projected ten-furlong time (10f), a projected turn time in a ten-furlong race (10fTT, the time to negotiate the distance between the six furlong and eight furlong markers) and a projected last quarter-mile time in a ten-furlong race (10fLQ).  

Next, we calculate Sartin Methodology-based Brohamer pace numbers ("Modern Pace Handicapping", by Tom Brohamer, William Morrow and Company, Inc,. New York, 1991) for the same races.  Evaluating only route races these are limited to a 3Fr (Final Fraction) number which is the speed in feet-per-second from the six furlong call to the finish and a %E (Percent Early) number which is a relative measure of energy used through the six-furlong call.  Speed types display %E figures significantly higher than off-the-pace types, although the absolute numbers are greatly affected by the distance of a race.  We emphasize 3Fr and %E from among the various available Brohamer figures because these are directly related to a horse’s ability to conserve energy and to finish its races with something left in reserve.

The other Brohamer figures include EP (Early Pace), the velocity in feet-per-second to the six-furlong call; SP (Sustained Pace), the average of Early Pace and the Final Fraction, thus relating a horse's speed to the six-furlong call and his ability to finish; AP (Average Pace), the average of EP and SP; 1Fr (First Fraction) and 2Fr (Second Fraction), the average velocities in feet-per-second between each of the first two calls (start to four furlongs and four furlongs to six furlongs); and TE (Total Energy), the sum of EP and 3Fr (the total available energy based on current conditions of distance, surface and track as well as inherent ability).

Finally, we use Performance Figures (PFs), based on the same linear regression technology described earlier, as a measure of the absolute quality of the races being analyzed. 

The detailed pace figures for this year’s leading Derby contenders are here. 

For reference, guideline numbers (all times are in seconds; e.g., 122.34 = 2:02.34) for all Derby winners since 1984 plus Spectacular Bid and Triple Crown winners Secretariat, Seattle Slew and Affirmed are: