05/01/2012 2:22PM

Kentucky Derby: Dosage and dual qualifiers


The Dosage theory, originated in the early 1900s and later modified and refined, contends that it’s possible to mathematically determine a horse’s performance potential over different distances, based on the presence of certain influential sires in the horse’s pedigree.

The system classifies those stallions -- termed “chefs-de-race,” or “chiefs of the breed”-- according to the distance aptitudes their progeny have shown. Today, the system uses five stallion categories, ranging from the high-caliber sprint sire designation “brilliant” to the stamina-oriented “professional.” The categories, in ascending order of stamina-siring proficiency, are brilliant, intermediate, classic, solid, and professional. The theory’s leading proponent, Steve Roman, periodically reclassifies sires and adds sires to these categories.

[KENTUCKY DERBY: Get PPs, watch analysis video, and read pre-race reports]

Dosage assigns points based on the chefs-de-race in a horse’s pedigree, then uses those points to calculate two numbers, called the Dosage Index and the Center of Distribution. According to the theory, the lower those numbers are, the longer the horse’s preferred running distance. Although it is used by some breeders, since Roman introduced his iteration of Dosage in 1981 the theory most commonly has been associated with Kentucky Derby handicapping. Dosage subscribers believe that only runners with a Dosage Index of 4.00 or lower are genetically predisposed to win the race, and many of the theory’s supporters point to the fact that, since 1981, 26 of the 31 Derby winners (including Animal Kingdom last year) qualified by Dosage score. On the other hand, the vast majority of Derby entrants each year do qualify. This year, 19 have indices below 4.00; the exception is Dullahan, whose Dosage Index is 4.20.

To narrow that field, many Dosage followers highlight “dual qualifiers,” horses who qualify on Dosage and also were either foreign champions or were weighted within 10 pounds of the highweight on the previous year’s Experimental Free Handicap ranking of 2-year-olds.

This year’s dual qualifiers are Creative Cause, Gemologist, Hansen, Liaison, Rousing Sermon, Sabercat, Trinniberg, and Union Rags.

But the dual qualifier angle has only had limited success. Only two of the last 14 winners, Street Sense in 2007 and Super Saver in 2010, were dual qualifiers.

Here is a look at this year's Kentucky Derby contenders and their dosage data:

Horse Dosage profile Dosage Index Center of distribution
Alpha 7-6-19-4-0 1.67 0.44
Bodemeister 9-9-12-0-2 3.00 0.72
Creative Cause 3-2-23-0-0 1.43 0.29
Daddy Long Legs 11-1-3-3-0 3.00 1.11
Daddy Nose Best 5-1-5-1-0 2.43 0.83
Done Talking 10-6-10-2-2 2.33 0.67
Dullahan 8-8-10-0-0 4.20 0.92
El Padrino 11-5-20-0-0 2.60 0.75
Gemologist 12-2-13-1-0 2.73 0.89
Hansen 6-5-6-1-0 3.50 0.89
I'll Have Another 2-4-7-1-0 2.11 0.50
Liaison 1-4-5-0-0 3.00 0.60
Optimizer 10-9-17-0-0 3.24


Prospective 8-5-11-0-0 3.36


Rousing Sermon 5-3-10-0-0 2.60 0.72
Sabercat 10-4-13-0-1 2.73 0.79
Take Charge Indy 6-13-19-0-0 3.00 0.66
Trinniberg 3-0-3-0-0 3.00 1.00
Union Rags 9-1-10-2-0 2.14 0.77
Went the Day Well 4-1-11-0-0 1.91 0.56