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Homeracing

The Real Value of a Length

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Derek Simon

June 27th, 2015

Perhaps the oldest and silliest horse racing rule of thumb in the history of old and silly horse racing rules of thumb is the notion that a length equals a fifth of a second. Although it has been shown — repeatedly — that this rule is not accurate, many horseplayers still swear by it.

In fact, for years, the British Horseracing Authority used the one-length-equals-one-fifth-of-a-second rule to determine official margins, even though it had actual finishing times to work with. In other words, rather than using the photo-finish strip to compute beaten lengths (as is the case in America), the BHP used the tape to calculate race times, which were then converted to beaten lengths — one fifth of a second at a time. This is akin to providing surveillance camera footage to a police sketch artist in hopes of obtaining a better rendering.


In early 2008, the BHP changed its practices, but only insofar as the conversion values were concerned. Now, different courses and track conditions dictate which new, but still silly, rule of thumb to use:

(From www.britishhorseracing.com)

Some of the speed figure guys, like Andrew Beyer, seem to understand that the value of a length is actually a function of time, yet most — if not all — persist in giving it a fixed value.

“The equation of one length with one-fifth of a second is used almost universally, but it is not quite accurate,” Beyer writes in Picking Winners. “A fast horse running in a sprint will obviously cover a length more quickly than a plodder going a mile and a half. The discrepancies are minor, and a reader whose head is reeling from all the figures on the previous pages [of his book] may ignore the following chart for converting beaten lengths into figures at varying distances.”

Beyer then offers a chart that gives the point values for various losing margins at different distances.

Of course, what Beyer and the BHP ignore is that the value of a length is not — and never has been — static at any distance. It is a dynamic measurement with a value that varies based on the time of the race.

For example, the value of a length in Secretariat’s win in the middle jewel of the 1973 Triple Crown was decidedly different than the value of a length in American Pharoah’s romp in that same race 42 years later. Assuming that a running horse is approximately 10-feet long from nose to rump, we get the following values of a length in those races:

Now, I realize that some may take issue with my assumption as to the average length of a thoroughbred, especially when a respected source like the Daily Racing Form claims that the typical racehorse is only about eight-feet long. But, remember, when horses run they tend to stretch their necks out and it is the running horse that we are attempting to measure, not the ones strolling about in the paddock or grazing in the pasture. Naturally, I’d love to see measurements from actual races — perhaps the average running horse is 9.8 feet or 10.2 feet — but, until I do, or hear differently from a reliable source (hint, hint), 10 feet seems to work pretty well.

I know what some of you are thinking: Who cares, Derek. What difference does a few tenths of a second make? Well, considering that the average race winner over any surface is victorious by less than three lengths, I think the answer is obvious.

VALUE OF A LENGTH (in seconds) = 1 ÷ [RACE DISTANCE (in feet) ÷ RACE TIME (in seconds) ÷ 10]

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