Fancy a flutter? Using science to pick the Derby winner.


The Epsom Derby, which takes place at the Epsom racecourse tomorrow (5 June 2021), is often considered the Blue Ribbon of flat racing. Horses that are successful in the race often progress to equally successful careers at stud and become leading influencers in future generations of racehorses. Tomorrow’s Cazoo Derby will see 12 colts line up, all intent on winning a share of the £1.5 million prize. But if you are planning a flutter, shouldn’t you be applying science, rather than luck, to boost your chances of picking a winner?

Thoroughbred racehorse success is often associated with horses’ breeding and a lot of emphasis is placed on the value of key performance traits such as stamina, equating to optimal race distance, and speed which can be influenced by a horse’s gait patterns e.g. stride length and how they ‘cope’ with different types of going, which are considered to be inherited. However, despite the continued emphasis placed on pedigree in the industry, research in this field suggests the heritability of most performance traits is relatively poor.

In 2010, Dr Jane Williams, Head of Research, Associate Professor at Hartpury University and renowned equine scientist, Dr David Marlin, decided to test this and collected data related to breeding, race performance, training and jockeys for horses that had run in the Derby between 1998 and 2009 to see if any factors could be identified with winning, using multivariable binary regression modelling (an epidemiological statistical technique). They found most factors did not appear to have any relationship with Derby success, but four markers were found to increase a horse’s chance of winning the race. These were:

1. being the race favourite increased the chance of winning by 4.75 times
2. the number of 2-year old wins increased the chance of winning by 1.45 times per win
3. being foaled in Ireland increased the chance of winning by 2.80 times
4. having the same jockey in all races throughout a horse’s career up to and including the Derby increased the chance of winning by 2.53 times

Based on these results the two scientists looked at the horses entered in the 2010 Derby and four horses stood out: ‘Jan Vermeer’, the race favourite, ‘At First Sight’, a 100-1 outsider universally dismissed as only being a pacemaker, ‘Rewilding’ and ‘Midas Touch’. The winner of the 2010 Epson Derby was ‘Workforce’ (starting price 6-1), a British Thoroughbred racehorse ridden by Ryan Moore in a course record time. In 2009 he had won one race and in 2010 he also won the Prix de l’Arc de Triomphe, both times ridden by the same jockey. ‘At First Sight’ led the race from the start and was only eventually overtaken just over 1 furlong from the finish to be beaten into 2nd place by just 7 lengths. ‘Rewilding’ was 3rd (starting price 9-2), the favourite ‘Jan Vermeer’ was 4th and ‘Midas Touch’ was 5th.

So what about this year’s race? Applying the key predictive factors Dr Williams and Dr Marlin found in their analysis of the field that two horses stand out: ‘Bolshoi Ballet’, the current favourite (and we should remember that favourite status was a key predictor of success and this horse may not be favourite at the start of the race!) and ‘One Ruler’ (currently a 25-1 chance). Another horse which is interesting is ‘Mac Swiney’ (currently 13/2 in the betting); this horse ranks midway in the field with the scientist’s model; however, in the horse’s career to date he has had the same jockey for all seven of his races since his first outing, and that same rider will also be riding him in the Derby. Therefore, the duo has selected him to meet the experienced jockey criteria and as a result, his chance of winning sits strongly above ‘Bolshoi Ballet’ and ‘One Ruler’ despite him not being the race favourite.

Are the scientists prepared to say that one of these horses will definitely win? No! But perhaps it is worth considering employing science as an alternative strategy for predicting tomorrow’s winner – best of luck!

Want to know more? The full paper is available open access at Comparative Exercise Physiology: HERE

Marlin, D.J., Williams, J.M. and Parkin, T., 2014. Improving the odds?
How to pick the winner of the English Derby. Comparative Exercise Physiology, 10(1), pp.57-62

Background on The Epsom Derby:
The Epsom Derby was first run in 1780 when the Earl of Derby introduced a one-mile race for three-year-old colts and fillies to complement The Oaks (the equivalent race for fillies only) which had been run the year before. Legend suggests that Sir Charles Bunbury was dining with the Earl of Derby at The Oaks and a coin was tossed to decide if the race should be called ‘The Derby’ or ‘The Bunbury’. Although the Earl of Derby won the toss of the coin, Sir Charles Bunbury’s horse won the inaugural race with the colt, Diomed. The distance of The Derby was increased from one mile to its current distance of one and a half miles in 1784. Today The Derby is one of five UK classic races and is the second leg of the English Triple Crown, preceded by the 2,000 Guineas and followed by the St. Leger.


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