Myth-Busting: A good big 'un will beat a good little 'un

Was Derby winner Workforce- a big-rangy colt- always destined for greatness?

In the latest installment to his myth-busters series, Simon Rowlands examines the old theory that size matters.

A few months in to this "myth-busting" series, I find that I am in danger of confirming nearly as many "myths" as I bust. So, please allow me some time out to bust the "a good big 'un will beat a good little 'un" myth on the grounds of feeble pedantry. 

As it stands, all that we know from the proposition is that both horses are of equal ability - that they are "good" - and therefore that neither has an advantage over the other. So the statement does not hold. 

Many axioms are glib, like this, but they persist because they imply the possibility of a deeper truth, in this case whether we should treat "big" horses and "little" horses precisely the same. The answer to that is more complex.

One implication of my earlier "Myth-busting: Weight does not matter (it does)" blog is that additional weight will have different effects on horses of different sizes in simple Newtonian terms. 

For instance, 140 lb (10 stones) represents an increase of 10.45% in the combined weight of body and jockey/equipment for a horse weighing 1200 lb and 12.28% for a horse weighing 1000 lb. Assuming that Force remains constant, and that the additional weight is distributed identically in both cases, additional weight will have a bigger effect on a smaller horse than a bigger one. 

Such assumptions are fine in theory, and prove a valuable point, but reality tends to be far messier. 

For example, a change in an individual horse's body weight is likely to be accompanied by a change in that horse's ability to exert Force. In particular, an increase in a horse's body weight may come with an increase in power which offsets, or more than offsets, that impediment. 

That is why horse body weights - were we to know them - would need to be looked at in both absolute (Newtonian) and relative (to the individual horse's optimum, which itself will change over time) terms. 

For another example, dead weight is dead weight, but different jockeys are likely to comprise different proportions of any jockey/equipment impost, and will have different aptitudes of distributing their own weight effectively.

These do not negate the theory, but they do show that, in reality, there are likely to be extraneous factors which complicate the issue and confound any attempt to come up with simple answers.

While it is not implied by the original "myth", there is also the question of whether a big 'un is more or less likely to be "good" than a little 'un. 

Sadly, while British Racing may be "Great" in some respects, it is not always great at providing information to engage the inquisitive. Never mind whether a good big 'un will beat a good little 'un, there is no official indication whatsoever whether a horse is big, small, or somewhere in between. 

Hong Kong is a jurisdiction in which body weights are officially recorded as a matter of course, but data there is confused by the fact that the small number of better races are mostly at longer distances and that horses at longer distances tend to be physically leaner than those at shorter distances. 

Fear not, though, as help is at hand. Timeform physical descriptions of horses have existed for many decades now. While the personnel responsible for these descriptions have changed over time, and while the descriptions are necessarily somewhat subjective, they are arrived at as professionally as possible and have stood the test of time.

If big horses were generally better than small horses, you would hope that it would show up here. And it does.

A study of Timeform physical descriptions from the 2011 Flat season gave the following findings: "big" median rating of 80 (279 cases); "small" median rating of 63.5 (116 cases). 

For the record, "attractive" 87 (165 cases) and "rangy" 84 (113 cases) were the best descriptions, while "plain" 57 (54 cases) and "sparely-made" 63 (55 cases) were the worst.

In summary, a good big 'un will not necessarily beat a good little 'un, but a big 'un is more likely to be "good" than a little 'un in the first place.