Monthly Archives: October 2010

The Wegman report sees red (noise)

By Deep Climate

The recent focus on George Mason University’s investigation into plagiarism allegations concerning the Wegman “hockey stick” report and related scholarship has led to some interesting reactions in the blogosphere. Apparently, this involves trifling attribution problems for one or two paragraphs, even though the allegations now touch on no less than 35 pages of the Wegman report, as well as the federally funded Said et al 2008. Not to mention that subsequent editing has also led to numerous errors and even distortions.

But we are also told that none of this “matters”, because the allegations and incompetence do not directly touch on the analysis nor the findings of the Wegman report. So, given David Ritson’s timely intervention and his renewed complaints about Edward Wegman’s lack of transparency, perhaps it is time to re-examine  Wegman report section 4, entitled “Reconstructions and  Exploration Principal Component Methodologies”. For Ritson’s critique of the central Wegman analysis itself remains as pertinent today as four years ago, when he expressed his concerns directly to the authors less than three weeks after the release of the Wegman report.

Ritson pointed out a major error in Wegman et al’s exposition of the supposed tendency of “short-centred” principal component analysis to exclusively “pick out” hockey sticks from random pseudo-proxies.  Wegman et al claimed that Steve McIntyre and Ross McKitrick had used  a simple auto-regressive model to generate the random pseudo-proxies, which is the same procedure used by paleoclimatologists to benchmark reconstructions. But, in fact, McIntyre and McKitrick clearly used a very different – and highly questionable – noise model, based on a “persistent” auto-correlation function derived from the original set of proxies. As a result of this gross misunderstanding, to put it charitably, the Wegman report failed utterly to analyze the actual scientific and statistical issues. And to this day, no one – not Wegman, nor any of his defenders – has addressed or even mentioned this obvious and fatal flaw at the heart of the Wegman report.

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David Ritson speaks out

By Deep Climate

David Ritson, emeritus professor of physics at Stanford University, has updated Steve McIntyre and the rest of the world on a key controversy concerning the Wegman Report, namely Edward Wegman’s ongoing failure to release supporting material related to the analysis within the Wegman report, more than four years after his promises to do so.

Here is Ritson’s complete comment, addressed to McIntyre at ClimateAudit.

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Wegman under investigation by George Mason University

By Deep Climate

[Update, Oct. 11: George Mason University spokesperson Doug Walsch has clarified that the complaint against Wegman has moved past the preliminary “inquiry” phase and is now under formal investigation. ]

[Update, Oct. 15, 19: I have added pointers to my previous discussions and updated side-by-side comparisons relevant to allegations of plagiarism forwarded to George Mason University last March and April. The allegations concern not only the Wegman report, but also the federally-funded  Said et al 2008  (published in Computational Statistics and Data Analysis, with Wegman and two other Wegman proteges as co-authors). ]

George Mason University has acknowledged that statistics professor Edward Wegman is under investigation for plagiarism. As related in USA Today, the investigation followed a formal complaint by paleoclimatologist Raymond Bradley, co-author of the seminal (and controversial) 1998 and 1999 “hockey stick” temperature reconstructions.

But a letter from Roger Stough, GMU’s vice-president responsible for research, indicates that the pace of the initial inquiry has been slow. And it appears that a promised date for resolution of the inquiry phase of the proceeding has been missed.

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