Ten of the eleven American Triple Crown sweeps have come in bunches, three in the 1930s, four in the 1940s, and three in the 1970s.  Why then has it been 37 years since Affirmed won the Kentucky Derby, the Preakness, and the Belmont?

Several plausible but largely unsubstantiated explanations have been offered, such as (a) horses of today are not bred to be as sturdy as their predecessors of 40 years ago and more; (b) dehydration caused by the anti-diuretic furosemide saps racehorses’ strength and prolongs their recovery time; and (c) trainers of today are not as proficient as the old-timers.

A statistically demonstrable principle is more likely, unless equine athletes are somehow immune to it.

Recently, a writer for the Wall Street Journal, Christopher Mims, adeptly described this principle “common to any number of human-made phenomena, including batting averages, the stock market, and the relative performance of economy and luxury automobiles.”  He could have included the relative performance of Thoroughbred racehorses.

To illustrate the principle, Mims said:  “Take Ted Williams, who in 1941 became the last hitter in major league baseball to bat over .400 in a season.  As observed by the late evolutionary biologist Stephen Jay Gould, the straightforward reason no one has matched Williams in the past 60 years is that all players in baseball have since become uniformly more skilled—including pitchers.  As best practices in training and recruitment spread, everyone has gotten better, and the difference between the performance of the worst player and the best one has narrowed.  In statistical terms, as the performance of players has increased, the variance in their batting averages has shrunk year after year.”

Home run feats by Babe Ruth provide another example of Gould’s explanation.  In every year from 1918-1932, except for 1925, the number of home runs hit by Ruth exceeded the total hit by entire major league clubs.  For instance, in 1920, Ruth’s home run total exceeded the home run output of 15 teams and in 1927 he hit more home runs than 12 teams.  This wide variance would be virtually impossible today because all MLB teams have players with the demonstrated capability to hit high home-run totals.

In addressing the question of why it has been such a long time since a horse won the Triple Crown, the most important issue is not whether horses of today are faster or slower than their ancestors, rather the main issue is whether the variances or standard deviations around the average running times for various distances have shrunk, and, in particular, for distances of 1 1/4 miles, 1 3/16 miles, and 1 1/2 miles.

To test this hypothesis, one would need to subject it to a large amount of data from a representative cross-section of races and racetracks.  However, there is no reason to presuppose that horse racing would be any different than other human phenomena, like the lessened performance differences between baseball players, mutual fund managers, and economy vs. luxury automobiles, etc.

With Thoroughbred horse breeders having access to the same stallions and trainers adopting uniform methods and best practices, the performance gap between the top racehorses and the worst racehorses has likely closed over the years.  Thus it takes an equine equivalent of a Ted Williams or a Babe Ruth to have the speed, stamina, and durability to prevail over his peers three times in races over a five-week period.

Maybe American Pharoah is an equine version of Babe Ruth or Ted Williams.  But we have had high expectations for other colts since 1978 and had our hopes dashed.

Copyright © 2015 Horse Racing Business


  1. What insight that I’ve never seen written about. I never thought about this empirical outcome but it makes sense.

  2. Pure chance. The twenty-five years between Secretariat and Citation, especially considering foal crop sizes, is not statistically different from the current drought. There have been more than a few horses which could have been Trlple Crown winners if circumstances unfolded differently – Point Given and Afleet Alex perhaps the two best examples of the last 15 years. And, there have actually been more dual classic winners during these three and a half decades than the historic average. That may actually indicate it is easier now to win the Triple Crown.

  3. Bill Shanklin says


    In evaluating the Triple Crown drought, the use of statistical significance is unnecessary and mathematically inappropriate because you are dealing with a census rather than a sample. No need to calculate statistical significance with a census. The 37 years since the last Triple Crown winner is 12 more years than the 25 years between Citation and Secretariat. That represents 12/25 = 48% longer…and that sure is significant.

  4. If Yriple Crown winners were born and not made – on the track within competition and subject to luck and circumstance – you might have a point.