Theories On Picking The Kentucky Derby Winner

Theories On Picking The Kentucky Derby Winner

last updated 5-1-09

There are countless ways people have used to try to predict who will win or who cannot win the Kentucky Derby. Some are relatively obscure, while others have gained in popularity over the years. Following are some I have run across. Judge their successfulness for yourself.

Note: All horse names on this page are highlighted in bold.

Dosage Index

This is by far the most popular way of winnowing out who can make the Derby distance of 1 1/4 miles and who can't. A simple explanation is that dosage figures a given contender's distance potential based on stallions from the first 4 generations of that horse's pedigree. It's a genetically-based theory that takes into account not only how well certain ancestors of the horse did, but also how far back in the horse's line they are. Points are awarded for speed and stamina of top-notch horses that often appear in contenders' pedigrees. These superstallions are called "chefs de race." Any horse with a dosage of 4.00 or less is supposed to be able to make the derby distance. So far, since the derby began in 1875, only four winners have had dosages higher than 4.00; however, all of those were relatively recently. They were Strike The Gold in 1991, Real Quiet in 1998, Charismatic in 1999 and Giacomo in 2005. Because of a reclassification of his sire, Strike the Gold would now qualify. 


Only one horse this year has a dosage over 4.00: Mine That Bird.

To learn more about dosage, visit the website of the creator of the modern day dosage system here.

Dual Qualifiers

Dual qualifiers are those horses that not only have a dosage of 4.00 or less but also are within 10 pounds of the high weight in the Experimental Free Handicap rating. It is based only on races from the contenders' 2-year-old season. The last Dual Qualifier to win the Derby was Street Sense in 2007.


Dual Qualifiers in this year's race are: Chocolate Candy, I Want Revenge, Pioneerof the Nile and West Side Bernie.

Raise A Native Sire Line

Twelve Derby winners so far had the horse Raise A Native in their sire line, meaning the line of male horses extending back directly from the sire. (In other words, the sire's sire, and his sire, and his sire, etc.)


Horses in this year's race with Raise A Native in their sire lines are: Atomic Rain, Desert Party, Dunkirk, Flying Private, Papa Clem and Pioneerof the Nile.


Juvenile Jinx

Only one horse who has won the Breeders Cup Juvenile has ever won the derby. It was Street Sense in 2007. The 2008 Breeders' Cup Juvenile winner was Midshipman. Unfortunately, he was injured this spring, so will miss the 2009 Derby.



Only one gelding has won the Derby since Clyde Van Dusen in 1929. That was Funny Cide in 2003. 


The only gelding in this year's field is Mine That Bird.


Only three fillies have ever won the Derby, Regret in 1915, Genuine Risk in 1980, and Winning Colors in 1988.


No fillies are in this year's field.


Unraced at 2

The last horse to win the Kentucky Derby without racing at age 2 was Apollo in 1882. 


Two horses will try this year.  They are: Dunkirk and Summer Bird.


3-year-old Preps

Big Brown, in 2008, was the first horse since Sunny's Halo in 1983 to win without more than 2 prep races at age 3.  Those trying this year are Hold Me Back and Mine That Bird.


Also, the vast majority had at least a third place finish in their last prep, but in 2005 Giacomo went on to win the Derby after having been 4th in his previous race.  This year, Atomic Rain, Mine That Bird and Nowhere to Hide were 4th in their last races and Flying Private and Join in the Dance were 5th in their last races.

Barbaro, the 2006 Derby winner, was the first horse since Needles in 1956 to win the Derby without a race four weeks or fewer before it. It should be noted, however, that this number is likely to increase because of the movement of the Florida Derby, a key prep race, to 5 weeks before the Derby.  Horses coming off a 5-week layoff this year are Desert Party, Dunkirk, Mine That Bird and Regal RansomFriesan Fire is coming off a 7-week layoff.


Post Position

Big Brown, in 2008, was the first horse to win from post position 20 (the far outside) since Clyde Van Dusen in 1929. This year Flying Private has the outside post position.


Muscle Power

This is the theory my great uncle (Marvin Stone) taught me years ago. The problem with it is that it works best when the horses are observed in the Derby post parade, and that's a little too late if you want to place a bet at the track. It's simple enough. Just look at the flank muscles on the horse while he/she is walking. Do you see a ripple effect? Do the muscles there appear bigger, more well-toned than those of the other horses? Is the coat shiny and does the horse appear fit? Of course, this theory is very subjective, but from what I can see, it may work the best in judging how a horse will do that day. Uncle Marvin died in June of 1988. I was 10. That year, Winning Colors, a filly, won. He picked her. I think he had picked the winner the last couple of years before that, too, but I can't really remember.



This is a common sense predictor, but it can only be used immediately before the Derby. Churchill Downs on Derby Day is a place full of commotion. Horses are many times upset by the crowd. They skitter sideways in the post parade or just in the walk over from the paddock. They often have trouble loading in the starting gate. Obviously, a horse with his mind on the crowd does not have his mind on racing. Also, a horse who uses up his energy in nervous tension before the race doesn't have as much when the race actually begins. 


Join in the Dance was quite jumpy when schooled in the paddock on Thursday.


LH-X (Large Heart) Factor

This is a relatively new theory based on the book The X Factor published in 1997 and available at In a nutshell, it says certain horses have a mutant gene that creates unusually large hearts (Secretariat's was estimated at 22 lbs. when the normal weight is about 8 lbs. for example) and that this gene appears to be sex-linked through the X chromosome. This means all of a large-hearted sire's daughters and none of his sons will have the gene. The daughters will pass them down to a statistical 50% of both sexes of their progeny. The percentage chance a given horse has this gene is then cut in half by each successive generation, following the X chromosome. Horses who could have a gene passed down to them from a large-hearted sire in his/her pedigree are said to have "roads" to those horses. For those who wish to find out more, check out Pedigree Query.


Beyer Speed Figures

Beyers are numbers invented by Washington Post turf columnist Andrew Beyer as a way to compare how fast different horses are on different tracks on different days. The higher the number, the speedier the horse is supposed to be. These numbers may change drastically for a horse from race to race as the horse gets fitter (and thus faster) or has problems.


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