The Dosage Method – The Alternative Analysis Tool Part Two

Guest post written by Ben Aitken from The Betting School

In part two, you can read part one by clicking here, of my introduction to Dosage series I’m going to explain to you how Dosage is calculated and exactly what the terms DP, DI, CD and DPA stand for.

How is Dosage calculated?

In order to better understand Dosage figures it is valuable to go through the actual procedure of doing the calculations. I would like to add, however, that you never need to manually work out a horse’s Dosage rating. The brilliance of the internet allows us to simply log onto www.pedigreequery.com (this is a free site) and search for the horse in question. Entering the horses name in the search box will bring up the horse’s pedigree and its Dosage rating. Even though Dosage figures are merely a mouse click away, seeing how the figures are generated provides a stronger knowledge of what these figures mean and how they relate to a particular thoroughbred. In my opinion it is extremely worthwhile understanding how the dosage figures are achieved.

To explain what the Dosage ratings mean we will use current Epsom Derby champion WORKFORCE as our example –

What is the Dosage Profile?

Put simply, the Dosage Profile is the total number of points this horse has inherited from influential sires in each category from its past four generations. Workforce has inherited 7 Brilliant, 1 Intermediate, 10 Classic, 4 Solid and 0 Professional points. This implies that Workforce has more speed in his pedigree than stamina; backed up by the fact he smashed the track record at Epsom on fast ground.

To calculate a horse’s Dosage Profile (DP) we must first look at its four generation pedigree; below is Workforce’s four generation pedigree. Chefs de-Race sires are in italics and the categories they have been assigned to are in brackets.

With this information we can now work out Workforce’s Dosage Profile. To make it easier to visualize I have put the previous information into the following table –

It is simply a case of adding up all the points that Workforce has inherited throughout the four generations in each individual category. By doing this the Dosage Profile is created. From the above we can see that Workforce’s Dosage Profile is 7-1-10-4-0.

What is the Dosage Index?

Once we have the DP we can work out the DI. The DI is the ratio of speed points in the horses DP compared to stamina points. In the DP the Brilliant and Intermediate categories are classed as speed and the Solid and Professional categories are classed as stamina. The points in the Classic category are divided equally between speed and stamina. To calculate a horse’s Dosage Index the following equation is used.

(Speed)

Brilliant + Intermediate + ½ Classic

Solid + Professional + ½ Classic

(Stamina)

If we were to apply this to Workforce then the equation would look like this –

7 + 1 + 5

4 + 0 + 5

This gives us Workforce’s Dosage Index of 1.44.

Along with the CD figure, which we will come to in a moment, the DI is an important figure when analysing and handicapping a race. The DI not only provides you with the distinction between a speedy and a stamina winner but also a numerical range within which the winners tend to fall. Horses with a DI above 1.00 have more speed than stamina and horses with a DI below 1.00 have more stamina than speed. For example, YEATS has a relatively low DI of 0.89 and his four Gold Cup victories at Royal Ascot adequately demonstrated this as he pounded his opponents into submission with not a turn of pace but by going for home early and keeping up a constant gallop that his opponents just could not match.

Below is DI expressed as a table with example horse’s and their DI rating’s –

What is the Centre of Distribution?

The CD marks the balancing point of all the numbers in a horse’s DP and is always a number ranging from +2 to -2. Again the CD is worked out from the DP and to calculate a horses CD the following equation is used –

((2 X Brilliant) + Intermediate) – ((2 X Professional) + Solid)

Total DP Points

If we were to apply this to Workforce then the equation would look like this –

((2 X 7) + 1) – ((2 X 0) + 4)

22

This gives us Workforce’s Centre of Distribution rating of 0.50.

The result of the formula will always be a number between +2 and -2. Theoretically the CD is an indicator of the distance a horse will be effective over. For example, 14 of the last 15 winners of the Queen Anne Stakes (run at Royal Ascot) have had a CD above 0.25. Using the following table you can see this range corresponds accurately with the distance this race is run over; one mile. From my research I have found that not only does the CD affect the distance capabilities of a racehorse but different tracks and even different conditions call for varying CD ratings.

As with the DI I have included a table to help you better understand the CD scale –

Unfortunately CD and distance are not always as directly related as this table above demonstrates, however this is a good indicator. Two horses with the same CD may be effective over varying trips such is the unpredictable nature of horse racing.

What is the Dosage Points Angle?

There are three categories within the Dosage point’s angle; Points Across The Board (PATB), Twenty+ (20+) & Dual Qualifiers (DQ). Horses that fit the PATB category are ones that have points in every column of their Dosage Profile; horses that fit the 20+ category are simply horses that have 20 or more points in total in their Dosage Profile; horses that fit the DQ category are ones that have points in every column of their Dosage Profile AND have 20 or more points in total in their Dosage Profile.

The following is an example of each of the three categories –

PATB – PERSIAN PUNCH – 3-1-4-6-2 (16) / 0.60 / -0.19

20+ – GOLDIKOVA – 9-6-18-0-3 (36) / 2.00 / 0.50

DQ – RITE OF PASSAGE – 3-2-17-1-1 (24) / 1.29 / 0.21

Throughout my initial period of analysing Dosage figures I noticed that these types of horses started to appear on quite a regular basis. I then started to question if these groups of horses held an advantage over horses that did not fit into one of the categories. I had already determined that under certain circumstances horses that were Dosage weak (less than eight points in total) were at a disadvantage to horses that had eight points or more but did this new angle take the method a stage further?

My analysis shows that overall (at the top levels) these horses appear in the list of winners with enough regularity to be given serious consideration when using Dosage to narrow the field.

As mentioned in my previous article, Dosage Ratings in their current form were developed by Dr Steven Roman who has a web-site (http://www.chefs-derace.com) and a book (Dosage: Pedigree and Performance) both dedicated to the subject.  I have taken these principles and applied them to British Flat and National Hunt Racing to give an alternative analysis angle on the top races run in the UK.

Ben Aitken

The Betting School provide a monthly report that is delivered to your door. This leading report has been edited by Darren Power and contributed to by some of the leading betting writers online. They have an active community that is involved in helping you find winning systems and strategies. Teaching how to analyse your chosen sport, create systems and build strategies is also covered.