Tag Archives: hockey stick graph

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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John Mashey on Strange Scholarship in the Wegman Report

Guest post by John Mashey

Strange Scholarship in the Wegman Report (SSWR)
A Facade for the Climate Anti-Science PR Campaign

This report offers a detailed study of the “Wegman Report”: Edward J. Wegman, David W. Scott, Yasmin H. Said, “AD HOC COMMITTEE REPORT ON THE ‘HOCKEY STICK’ GLOBAL CLIMATE RECONSTRUCTION”(2006).

It has been key prop of climate anti-science ever since. It was promoted to Congress by Representatives Joe Barton and Ed Whitfield as “independent, impartial, expert” work by a team of “eminent statisticians.” It was none of those.

A Barton staffer provided much of the source material to the Wegman team. The report itself contains numerous cases of obvious bias, as do process, testimony and follow-on actions. Of 91 pages, 35 are mostly plagiarized text, but often injected with errors, bias and changes of meaning. Its Bibliography is mostly padding, 50% of the references uncited in the text.  Many references are irrelevant or dubious.  The team relied heavily on a long-obsolete sketch and very likely on various uncredited sources. Much of the work was done by Said (then less than 1 year post-PhD) and by students several years pre-PhD. The (distinguished) 2nd author Scott wrote only a 3-page standard mathematical Appendix.  Some commenters were surprised to be later named as serious “reviewers.”  Comments were often ignored anyway.  People were misused.

The Wegman Report claimed two missions: #1 evaluate statistical issues of the “hockey stick” temperature graph,  and #2 assess potential peer review issues in climate science.  For #1, the team might have been able to do a peer-review-grade statistical analysis, but in 91 pages managed not to do so.  For  #2, a credible assessment needed a senior, multidisciplinary panel, not a statistics professor and his students, demonstrably unfamiliar with the science and as a team, unqualified for that task.   Instead, they made an odd excursion into “social network analysis,” a discipline  in which they lacked experience, but used poorly to make baseless claims of potential wrongdoing.

In retrospect, the real missions were: #1 claim the “hockey stick” broken and #2 discredit climate science as a whole. All this was a facade for a PR campaign well-honed by Washington, DC “think tanks” and allies, underway for years.

Most people can just read the 25-page main discussion, but 200+ pages of backup text are included to provide the necessary documentation, as some issues are potentially quite serious.

For a quick download, read the Executive Summary (first six pages). Then, here is the complete report, including the main discussion and 200+ pages of appendices.