As a result of the Weblog Awards contest, I’ve been introduced to a number of blogs, such as Bad Astronomy and Pharyngula, of which I’d been previously unaware, although they are both popular and have a loyal following. Bad Astronomy has a set of links to what it calls Anti-Antiscience sites, which include their rival Pharyngula and similar sites. “Anti-antiscience” seems to include astrology, mentalism, things like that; Phil Plait on Bad Astronomy mentions James Randi a number of times. I followed one of the links to a site called Memoirs of a SkepChick, one of whose recent posts was a review of Criss Angel’s (pseudo ?-) altercation with a contestant on Phenomenon:
After his pathetic nightclub act, Callahan was praised by the Cosby kid, the host of the show, and Uri Gellar (of course). Criss Angel then whipped out an envelope and offered Callahan and Gellar a million dollars of his own money if they could tell him what was written inside the envelope. Instead of immediately going back into his fake trance, Callahan called Angel an ideological bigot and lunged at him in what I suspect was intended to be a threatening manner.
Which gave me the following thought: the focus of this site is also “anti-antiscience”. The SkepChick is against lame parlor tricks and pathetic nightclub acts; so am I. MBH98 statistical methodology is essentially a parlor trick – a point that becomes obvious to any statistician that has spent the time to investigate it (a point clear to Jean S and UC as well as myself). It’s not just the principal components methodology – although the principal components methodology was highly relevant to the show in the initial presentation of the parlor trick. When the principal components aspect of the trick was exposed, they re-tooled the trick (in Ammann and Wahl who use prior results from realclimate without attribution) so that the woman still appears to be sawed in half even without using principal components. And all the innocent climate scientists say WOW!
One of the purposes of statistical analysis is to expose parlor tricks, especially where there is self-deception on the part of the scientists. In our first articles, we criticized several aspects of the parlor trick in MBH98. We did not say that this was the only parlor trick in the world or that this was the only way that the magician’s assistant could be sawed in half. So when the magician’s assistants and serial coauthors, Ammann and Wahl, write that you can still saw the woman in half without using principal components as part of the trick, it doesn’t mean that our criticism of the original parlor trick was wrong – only that they’ve re-tooled the trick a little and you have to watch for the pea under the thimble. I’ve discussed their particular pea under the thimble before – and, in its own way, the overfitting in Ammann and Wahl should be even more embarrassing to the climate science trade than MBH98 ( see posts here , especially here here here .
I’ve tried to tread a careful line in which I’ve been critical of these lame parlor tricks without presuming that the entire AGW theory depended on lame parlor tricks. It seems obvious to me that policy should not depend in any measure on parlor tricks – even if the policy ultimately proves to be the right policy. In addition, I think that it doesn’t even do people concerned about AGW any good to use things like MBH and its cousins. They should swear off such parlor tricks and focus on their best arguments. They might find that the effort sharpens their own presentations and makes them more convincing. (And, as readers of this blog know, we have thus far been unsuccessful in locating a straightforward engineering-quality exposition of how doubled CO2 leads to 2.5 deg C warming. I’m not saying that such an exposition is impossible; merely that reliance on things like MBH has perhaps diverted scientists from the expositions that they should have been working on.)
After a while, it becomes a bit discouraging that the MBH parlor tricks continue to re-surface under various guises, that climate scientists seem to believe in these tricks and that so many climate scientists apparently don’t understand how the tricks work. It really doesn’t give third party statisticians a very good impression of the acumen of the trade.
In passing, it’s interesting that Phil Plait of Bad Astronomy has also made an issue of data suppression. In a recent post entitled NASA suppressing aeronautic data: Part II, he said:
The bottom line is that Luedtke was 100% in the wrong about not releasing the data, and his reasoning for doing so is garbage. Griffins response was fine until he tried to spin this, which was also garbage.
You’d think that someone who thinks like this would support the campaign to make Lonnie Thompson and other climate scientists release their data, especially when, as in Lonnie Thompson’s case, the data is used in Al Gore’s hockey stick, some of it is over 20 years old and inconsistent grey versions have been circulated.
In reading the anti-antiscience comments, I was reminded of a famous comment by Keynes in 1940 in his review of early econometric models – and one that should always be kept in mind when considering complicated models:
But my mind goes back to the days when Mr Yule sprang a mine under the contraptions of optimistic statisticians by his discovery of spurious correlation. In plain terms, it is evidence that if what is really the same factor is appearing in several places under various disguises, a free choice of regression coefficients can lead to strange results. It becomes like those puzzles for children where you write down your age, multiply, add this and that, subtract something else and eventually end up the number of the Beast in Revelation.
Bad Astronomy is against people taking parlor tricks seriously. So are we.