Friday, May 08, 2009

More press release hype...sigh...

I suppose this sort of thing is so common it's hardly worth mentioning, especially if I cast my net wider than climate science. But given my interest in cycling and especially dodgy statistical analyses thereof, it caught my attention.

"Cyclists killed in Britain up by 11% in three years" screamed one headline. And looking at the press release, this is the only number given: the relevant sentence is "The number of cyclists killed or seriously injured fell from 2000 to 2004, but rose again by 11 per cent from 2004 to 2007, despite the amount of cycling staying broadly constant."

Note first that 11% refers to the number killed or seriously injured, of which the latter is overwhelmingly dominant (about 95% of the total). There are only about 100-150 cycling deaths a year, so there are bound to be large interannual fluctuations for that anyway. But more importantly, the full report - even the executive summary which is cunningly concealed by the sneaky trick of prominently displaying it on the main web page for the report, and which therefore no journalist will have bothered to read - also says that deaths for cyclists have dropped by a whopping 27% since 1994-1998, which is the baseline for official targets etc. However that doesn't make for an attention-grabbing headline, so didn't make it into the press release. While the recent blip up since 2004 (which was deliberately cherry-picked as the lowest point in the record) might be worth thinking about, it is hard to see it as conclusive of a real trend. Cycling levels are not measured very accurately and a few well-time tube strikes in London could easily get a lot of people on their bikes.

One can imagine the equivalent headline "global temperatures drop x.xx since 1998". Well we don't have to imagine it, since it's the sort of nonsense the septics regularly come out with. But I expect Govt departments to do rather better than that. Harrumph.

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