Right now, I’m working on two main projects where I intend to produce papers for journals: one is on the non-robustness of the “other” HS studies; the other is on MBH98 multivariate methods. The latter topic is somewhat “in the news” with the two Bürger articles and with the exchange at Science between VZ and […]
By Stephen McIntyre
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Also posted in MBH98, Multivariate, Replication
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Tagged algebra, borga, magnus, multivariate, orthogonal, overfit, pls, stone, stone and brooks
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Rutherford et al 2005 (the et al being half the Hockey Team: Mann, Bradley, Hughes, Briffa, Jones, Osborn) is a re-statement of the MBH98 network (flawed PCs and all) and the Briffa et al 2001 network using RegEM. I haven’t figured out exactly what the properties of the RegEM method are as compared to other […]
The question for today is how does realclimate go from tree ring series with autocorrelation functions that look like the one in the figure below to a claim that these proxies have an AR1 coefficient of 0.15. We know that they are pranksters, but this looks like a good prank and it is. Autocorrelation Function […]
"Standardization" and averaging are operations that are done time after time in paleoclimate studies without much discussion of the underlying distributions. If one browses through recent statistical literature on "robust statistics", one finds much sophisticated analysis of how to handle outliers. The term "robust" is commonly used in paleoclimate, but the term as used in […]
[Steve: Editorial comment] – This is John A’s post. I do not agree with his editorial flourishes linking this to models. I view the following as illustrating the defects of sole reliance by multiproxy reconstructions on the RE statistic – a statistic for which there are no distribution tables and which is little known or […]
While the Hockey Team like to talk about "moving on", in most scientific disciplines, articles of substance usually remain of continuing interest, since there had to be some interesting insight to have created the substance in the first place. I’ve been backtracking through some of the tree ring literature to try to fully understand how […]
Nature’s Guide to Authors includes an excellent statistical checklist which authors are asked to comply with to "ensure statistical adequacy". I’ve reproduced the checklist below, bolding a couple of interesting criteria. Readers of this blog can readily imagine how this checklist would apply to MBH98 or, for that matter to Moberg et al [2005]. One […]
DF criticized my post on principal components yesterday as follows: Most of your figures for conventional PC analysis are misleading. You are comparing PCA1 to mean as if PCA1 has an intrinsically meaningful scale, when it does not. If you rescaled your comparison plots so that PCA1 and the mean had the same variance, then […]
TCO has been pressing about the exact impact of various properties of the MBH PC methodology, asking some "elementary" questions about PC impact. Some readers have criticized him for in effect asking for a tutorial on PC methods. However, if someone asked: where can I find an article showing the statistical properties of PC methods […]
While Steve is away, and in honor of the NAS Panel which is so convivially considering the question of the reconstruction of past climate, Dave Stockwell decided to do his own reconstruction using exactly the same methodology as the Hockey Team. As you can see, his results are clearly consistent with the results of the […]
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