Saturday, June 11, 2011

By their follow-ups shall ye know them

Here's one you can use to judge the motives of (ahem) certain fair-n-balanced news outlets by. If you draw some useful conclusions about your own outlet's performance, that's OK too:

Climate warming since 1995 is now statistically significant, according to Phil Jones, the UK scientist targeted in the "ClimateGate" affair.

Last year, he told BBC News that post-1995 warming was not significant - a statement still seen on blogs critical of the idea of man-made climate change.

But another year of data has pushed the trend past the threshold usually used to assess whether trends are "real".

"Still seen on blogs critical of the idea of man-made climate change" is a bit of an understatement. The bombshell news at Fox and the Daily Mail in February 2010 was that one of those grant-grubbing liberal science fraudsters had finally confessed that there had been no global warming since 1995!!1!!!!1!! And that, friends, was a porky. Asked whether he would agree that there had been no statistically significant global warming since 1995, he answered, "Yes, but only just" -- or, as he went on to clarify, not at 95% confidence but "quite close."

This isn't a huge development; basically, a trend that was significant at p<.10 is now significant at p<.05, and Jones himself reiterates a point he made last year:

"Basically what's changed is one more year [of data]. ... It just shows the difficulty of achieving significance with a short time series, and that's why longer series -- 20 or 30 years -- would be a much better way of estimating trends and getting significance on a consistent basis."

Still, it does illustrate a couple of consistent problems with news practice that the partisan press is quite successful in exploiting. One is that journalism doesn't have a good mechanism for handling follow-ups on questionable assertions; however well the old tickler file might have worked, it didn't have a category for "hey, remember that bogus story that Fox ran last year?"

Another is that we don't deal with probability-based conclusions very well. That's a specific case of a broader concern: Loud and conclusive always trumps quiet and tentative. But either way, it gives an advantage to a story whose thrust is "HA HA Algore makes stuff up, science is all about who argues the loudest" over one that says "here's the confidence level at which we can support a tentative conclusion about a small-to-moderate effect that looks interesting in light of a number of other findings."

I'm not suggesting we wait with bated breath until Fox runs a zomg* GLOBAL WARMING IS REAL NOW!!!1!! hed; if your working assumption, like mine, has been that Fox is a party organ rather than a news outlet, that's appropriate. But you can draw conclusions from what your own news outlet -- the one you work for or the first one you open in the morning -- has been up to with this story. A story suggesting that what was once marginally significant evidence has now reached the professional standard would be appropriate. And when the foamy-mouthed callers demand your head, tell them to go cancel their own damn subscriptions. 

* Happy now, Cowan? I'm still debating whether to add this one to the HEADSUP-L style manual.



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