Tuesday, 23 August 2011

Sports and science journalism

Thomas Lumley's fed up with lazy reporting in the sciences:
if a press release or a wire service story told you that the Wallabies had a new training regimen that would improve their game without making them fitter, faster, tougher in the scrum, more accurate with kicking, or better at putting in the elbow, you’d ask questions. We’d like to see science journalism eventually get up to the standard of sports journalism.
He points the finger at journos who gulped down the claim that an hour of TV watching costs 22 minutes of life expectancy [which I'd critiqued here]. And, because his stats-fu is better than mine (and probably because he read the studies a bit more closely than I did), he notes:
The journal, in its blog, says that the real story was about sedentary lifestyles vs exercise.  They are shocked — shocked — to find that there might be sensational news coverage of the article. However, they do note:“The blast of news coverage also suggests that creative research angles on behavioral health impacts are useful in grabbing the public imagination.” Indeed.
The really strange thing about the paper, though, is the 22 minutes of life lost per hour of TV.  Looking at the confidence intervals shows that there is huge uncertainty (the range is from 20 seconds to 45 minutes), but it still doesn’t really make sense.  Some of this is just correlation vs causation — in reality, not everyone who spends the evening in front of the TV would spend the time jogging, or even playing golf, if their Sky subscription were cut off.   The other component is the model used for years-of-life lost.  The researchers didn’t actually do anything with individual participant data from the AusDiab study. They took the results of a previous analysis (which didn’t get nearly as much coverage) and added in the assumption that the effect of TV weakened with age.  Under that assumption, the effect must be a lot larger for younger people than it appears, and since younger people have more minutes of life to lose, that increases the average cost of TV.  The assumption was described  by the authors as if it was a universal fact, and it’s true that several important risk factors follow this pattern — one reason is that there are more things to die of at older ages, which applies here, but another is that, eg, low blood pressure in older people happens for bad reasons as well as good, and that doesn’t apply here.  In any case the attenuation assumption is doing a lot of the work, and it is only weakly connected to any actual data.
I'm very pleased that there's somebody else out there who cares about this stuff. It's really a bit pointless though. Papers exist to sell eyeballs to advertisers. Most of those eyeballs are in front of squishy grey stuff that doesn't care a whole lot about scientific accuracy but rather about group affiliation and sensationalism. The real problem is on the demand side. We get the journalism we deserve. Just like we get the politics we deserve.

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