Friday, 1 May 2009

Lies, damn lies...

There was an interesting exchange of letters in this week’s Times. On Monday, Professor Ian Gilmore, one of our leading anti-drink bansturbators, wrote the following:

Carol Midgley suggests that “Middle England” drinkers are unlikely to die from overconsumption of alcohol.

A recent University of Southampton study of liver ward patients found all but one with alcohol-related liver problems were daily or very frequent drinkers as opposed to binge drinkers. One quarter were drinking 40 units or fewer a week — this is roughly equivalent to half a bottle of wine on five nights a week. Put simply, Middle England drinkers are ending up on liver wards by regularly consuming what some might consider moderate levels of alcohol.
The dubiousness of his “half a bottle of wine” figure was rapidly pointed out by two correspondents, including David Ryder of Middleton who said:
Professor Gilmore’s wine would need to be at least 24 per cent alcohol content. Could the professor inform me as to where I could obtain this heady vintage?
And then Gilmore was taken to task by no less than Professor David J. Hand, the President of the Royal Statistical Society, for the “error of the transposed conditional”:
The premise shows that if one is a liver-ward patient then the probability of being a daily or frequent drinker is very high. But it says little directly about the probability of being on a liver ward, if one is a daily or frequent drinker — which is surely what one is interested in.
A further point is that, while it might be true that a quarter of liver ward patients were drinking 40 units or less (although I doubt this, as heavy drinkers habitually understate their own consumption), what proportion of those who drink 40 units or less end up on liver wards? I suspect it is extremely low. It would also be interesting to know how it compared with, say, the proportion of regular steak eaters who suffer heart attacks. Let us know the risks so we can judge for ourselves, and if you never take a risk, you never do anything.

1 comment:

  1. ....or, as my statistics professor used to say, "figures cannot lie, but liars can figure".

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