February 14, 2014

Statistical improvements in advertorials

The Herald has a headline “Why internet adultery numbers are soaring“, but doesn’t actually say why, or even provide any real evidence that they are increasing.

The news is that the number of people signed up to the website AshleyMadison is increasing as they expand internationally, but we’re not given any indication that the number of active members in a given area is increasing, let alone any data on how much actual goings-on is going on. So, the only internet data in the story would be relevant in the business section of the paper, but the Herald has the story filed under “Relationships & Pets.”

There is a gesture towards data later in the story

According to figures in the Journal of Marital and Family Therapy, some 22 per cent of men and 14 per cent of women will cheat on their spouses at least once during their marriage.

but this is basically useless for the headline claim about numbers soaring, since these are one-time percentages, and we aren’t even told when or where they are from. It looks as though they are probably from this 2005 paper, which summarises data back to the 1980s.

On the positive side, though, this is enormously better than the one from two years ago which had astonishingly bad use of data, completely ignoring denominators

If your partner supports National, has a PC, drinks Coke, eats meat, has a tattoo, smokes and is a Christian, be warned – they could be a cheater.

Progress, of sorts.

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »