Joe Barton‘s Committee has released a report they commissioned on the hockey stick by Wegman, Scott and Said (WSS). The focus of the report is much narrower than the NRC report and the results are basically a subset of the NRC report. In particular, both reports find that “off-centre” method used in Mann Bradley and Hughes’ 1998 paper (MBH98) tended to produce hockey stick shapes in the first principal component (PC1). Unfortunately, WSS stop there and do not address the question of what difference this makes to the reconstruction (which is not the same as PC1). The NRC panel did address this question and found that it made little difference.
It would be cynical of me to suggest that the terms of reference for WSS were crafted so that WSS would only check this aspect of MBH98 and not whether it made a difference to the reconstruction. Not surprisingly, the usual suspects are using WSS to claim that the hockey stick is shattered into a bazillion pieces. For instance, the Wall Street Journal editorial page:
[WSS’s] conclusion is that Mr. Mann’s papers are plagued by basic statistical errors that call his conclusions into doubt. Further, Professor Wegman’s report upholds the finding of Messrs. McIntyre and McKitrick that Mr. Mann’s methodology is biased toward producing “hockey stick” shaped graphs.
Needless to say the NRC panel’s findings are never mentioned in the WSJ editorial. (Nor in the WSS report for that matter.)
Wegman, Scott and Said are statisticians, not climatologists and this has lead to some errors in their interpretation of the literature. For example, the temperature graph in the first IPCC report is schematic and not quantitative, but they interpret it as if it was quantitative.
WSS do have a section that is not a subset of the NRC report — Chapter 5, which claims to present a Social Network Analysis of authorships in temperature reconstructions. They have some pretty graphs but there is no quantitative analysis. It’s possible that the temperature reconstruction community is so small that it causes difficulties with peer review but WSS don’t have any numbers to support this. I think such an analysis would require you to come up with a quantitative measure and compare with other authorship networks.
All in all there seems little reason to refer to this report rather that the NRC one.
But the most serious flaw in WSS is this claim:
This committee does not believe that web logs are an appropriate forum for the scientific debate on this issue.
I mean, really.