How long is a length? It's a bit like a piece of string

To celebrate the countdown to Christmas, the Racing Post is giving away one piece of paid content free each day. Here, in his unmissable weekly column, Tom Kerr examines the sometimes confusing method racing uses to determine finishing distances

It's a hoary old chestnut about racing that it has a terminology alien to the average man or woman: all furlongs and maidens and bumpers, stuff that means about as much to most folk as hogsheads and firkins. But one term, at least, is straightforward enough: a length; as in the length of a horse.

That's how we measure our sport, how we judge finishing margins, the value of form and – ultimately – superiority. So when we say that Bristol De Mai won the Betfair Chase by 57 lengths the other month we can state he won a Grade 1 by the longest distance any horse has recorded since the turn of the century.

A length is a nice, simple term, which simultaneously carries that euphonious tenor of anachronistic racing lingo while also being more or less accessible to all. Yet – and with apologies to the folks who already know what I'm about to say – as with so many aspects of racing, it is not as simple as it appears on the surface.

When Bristol De Mai won the Betfair Chase the judge didn't calculate the winning margin by measuring the distance with a picture snapped via some ridiculous wide-angle camera – that wouldn't make any sense, because the winning margin must be a reflection of when the second, Cue Card, actually passed the post, not where he was when Bristol De Mai won.

The winning distance of 57 lengths was therefore calculated by measuring the time it took Cue Card to cross the post in second then running that time through a formula known as the lengths-per-second scale. This is the little secret of a length – the gotcha for those racing novices who think this is one term they grasp. A length isn't really a unit of distance. It's a unit of time, masquerading as distance. And the more you look at this system, the less sense it actually makes.

How it works

To explain why, let's look at the calculations underpinning Bristol De Mai's 57-length winning distance. The lengths-per-second scale is not one size fits all: it varies according to code – Flat, all-weather or jumps – and going. Since this was a jumps race run on heavy ground the lengths-per-second scale was at its lowest possible level: four lengths per second. Cue Card finished 14 and a quarter seconds behind Bristol De Mai, hence the 57-length distance.

Had the race been run on good ground, however, the calculation would have been five lengths per second rather than four, so a winning distance of 71.25 lengths, rounded down to 71 lengths.

This happens because, reasonably enough, it is assumed that a horse running on good ground is likely to be finishing the race at a faster pace than a horse running in the same race on heavy ground. The same logic applies to Flat and all-weather races, which have their own lengths-per-second scales.

Yet, confusingly, while the scale varies according to code and going, it does not adjust for distance.

So the finishers in the Epsom Dash, the world's fastest five furlongs, are allotted their distances using the same formula as in Royal Ascot's Gold Cup over two miles four, despite the fact that the runners in each race are almost certainly moving at quite significantly different speeds come the finish line.

Jump races like the Eider can finish at walking pace, skewing winning margins relative to faster-run racesCredit: John Grossick

Even worse is the effect on some jumps races. So long as they are run on the same ground, the same lengths-per-second scale is applied to the finishers in a freewheeling two mile hurdle or bumper as in something like the Eider, where runners have been known to plod home at not far above the pace I walk to work.

The difference this creates in actual distance can be considerable. The average length of a horse is around 2.5 metres and a horse that finishes hard-running at 30mph is covering 13.4 metres per second, while one going at 15mph covers 6.7 metres in the same time. If both finish one second down the one running at 30mph was about 5½ lengths behind the winner and the one going 15mph was about 2½ lengths adrift, yet the recorded winning margin will be identical (4 lengths on soft going, for example).

Intrinsically inaccurate system

This confusing and unsatisfying situation could be partially remedied by extending the lengths-per-second scale to account for race distances as well as going and code, but that's not really the problem here. The issue is this guessy and intrinsically inaccurate system is a consequence of attempting to do the impossible: present a unit of time as a unit of distance (it's like the airport PA telling you your flight boarding closes in 500 yards).

The system then compounds the problem by trying to make this pretend unit of distance look more believable by rigidly adjusting for some, but by no means all, variables in a race. The end result is to obscure the one accurate measurement of finishing margin we actually have: the time.

All of this is akin to the Olympics deciding to start measuring winning margins in track events by taking the time back to second, running it through a formula based on wind direction and surface water (but not race distance) and then expressing it in trainer-lengths between finishers, despite that number having no relevance to the actual distance back to second. Doesn't make a great deal of sense, does it?

Ah yes, some will say, but everyone knows that lengths are really a measurement of time not distance. And perhaps that is true among racing pros - although in my research for this article I came across several 'expert' websites that gave incorrect or outdated versions of the lengths-per-second scale.

Yet even if experts do properly understand how winning margins are calculated, it is hardly surprising if the casual observer or punter believes that something called a winning distance and expressed in noses, heads and lengths is a unit of distance in some way comparable to inches, feet and yards.

How to fix it

Aside from being almost comically misleading, this becomes problematic for a couple of reasons. First, it undermines the appeal and fairness of one of the most popular special markets in racing: winning distance bets. Second, it makes form far harder to accurately gauge, since punters must know the lengths-per-second scale in use to grasp a winning margin's true worth.

Clearly, there are steps that could be taken to make this fairer and more transparent for all. As mentioned, the lengths-to-second scale, which attempts to translate time into distance in a vaguely coherent manner, obviously ought to be expanded to account for the differences in long and short races.

More importantly, the times underpinning winning distances, which are already being recorded to calculate the official margins, should simply be published alongside winning margins. That way we get the best of both worlds: a treasured part of racing's terminology remains intact, but those who wish a more scientific – and accurate – measure of form get that too.

So a straightforward solution to a complex problem, really, or as we might once have put it: as easy as shooting fish in a hogshead.

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