Sex Surveys: The Rule Of Three

[There is] an enigma that has dogged sex surveys for years: every time one is conducted, he writes, “something very odd” happens. For example the 2010 Health Survey for England revealed that in a lifetime men have an average of 14 partners, exactly double that of women. Spiegelhalter says that, for this type of statistic, that is “mathematically impossible”.

“Surely, if they are having sex with each other, the figures should be exactly the same,” he writes. The mismatch has been attributed to how the different genders do their totting up. “Men consciously or unconsciously exaggerate, while women underreport to fit in with social norms.” In other words men round up and women round down. One explanation is that men tend to include events that women would rather forget and thus don’t count.

This anomaly has been referred to by some as the rule of three. Put simply it holds that when a woman reveals how many people she has slept with you can safely multiply it by three and when a man does you can divide it by three because he’ll play up his boss-shagger credentials...

The Times.

Basically, any sex survey should be taken with a very large pinch of the salty stuff.

I know, who knew???

This piece is puffing a new book, Sex by Numbers: What statistics can tell us about sexual behaviour by David Spiegelhalter.

David Spiegelhalter, Professor of Risk at Cambridge University, is here to unravel the web of exaggerations, misdirections and downright lies that surround sex in modern society.*

I guarantee this book about 'sex and the Brits' will be all over the media soon; which perhaps tells you much about British attitudes to sex, ie we're obsessed but basically fucked.

* Fagburn likes David's book (and website), The Norm Chronicles: Stories about numbers and dangers, very much.