Hockey stick now in splinters

by William Yeatman on September 14, 2004

in Science

Canadian researchers Steve McIntyre and Ross McKitrick have published an update on their work that raises even more doubts about the legitimacy of the so-called hockey stick temperature reconstruction of the University of Virginias Michael Mann and colleagues (MBH98).

Nature magazine, in which MBH98 originally appeared, recently published a Corrigendum by Mann, which corrects some of the errors uncovered by McIntyre and McKitrick.  Nature had also agreed to publish a further 800-word criticism by McIntyre and McKitrick of the methodology and results obtained by MBH98.  However, after adding a third reviewer who was much less supportive of their findings than those who recommended publication of the initial submission and after reducing the number of words allowed for the piece to 500, Nature informed McIntyre and McKitrick that they had decided against publishing their article.

Nature said, In the light of this detailed advice, we have regretfully decided that publication of this debate in our Brief Communications Arising section is not justified.  This is principally because the discussion cannot be condensed into our 500-word/1 figure format (as you probably realise, supplementary information is only for review purposes because Brief Communications Arising are published online) and relies on technicalities that do not bring a clear resolution of the underlying issues.

McIntyre and McKitrick comment that, This decision primarily reflected the views of the new reviewer, who stated: Generally, I believe that the technical issues addressed in the comment and the reply are quite difficult to understand and not necessarily of interest to the wide readership of the Brief Communications section of Nature. I do not see a way to make this communication much clearer, particularly with the space requirements, as this comment is largely related to technical details.  In other words, Nature decided that a discussion of fundamental issues of how the hockey stick was arrived at would not be of interest to many people.

McIntyre and McKitrick have posted their draft submissions and correspondence with Nature at  The site also discusses another aspect of their work, an investigation into various lacunae and additional inaccuracies in MBH98.  In the process, they describe how neither Prof. Mann nor Nature magazine have provided access to important parts of the data on which MBH98 relies.

They comment, Reluctance on the part of Mann et al. and Nature to produce the results for their experiments, and in particular for the AD1400 step, would be one thing if the source code that generated them were available; but the refusal to provide either one is completely unjustifiable, especially since Nature based its decision against our paper, in part, on claims about the RE statistics that can only be verified by looking at the “experiment” results.  We surmise, based on our implementation of the methodology, that the R-squared and Coefficient of Efficiency (as this is defined in paleoclimate studies) statistics fail to reach statistical significance for the AD1400 step. It may also show that there are other problems in MBH98 besides the ones that we have described already.

They conclude, While we are frustrated that the time invested in the Nature process did not result in their willingness to correct the publication record therein, it did at least allow us to clarify several methodological issues, especially the crucial role of the controversial bristlecone pine series.  We will submit a revised article to a peer reviewed publication.  We have also submitted an abstract for a planned presentation at the forthcoming AGU meeting in December.

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