Replication #5: the Corrigendum Criterion

The MBH98 Corrigendum purported to explain the discrepancy of 35 series between the series listed in the original SI and the series actually used as follows:

These series, all of which come from the International Tree Ring Data Bank (ITRDB), met all the tests used for screening of the ITRDB data used in Mann et al. [1998] (see Mann et al. (2000)), except one”¢’‚¬?namely, that in 1997, either it could not be ascertained by the authors how these series had been standardized by the original contributors, or it was known that the series had been aggressively standardized, removing multidecadal to century-scale fluctuations.

In this note, I show that these criteria do not explain either the exclusion of many of the 35 series or the seemingly inconsistent inclusion of series, which have been "aggressively standardized". For example, the Corrigendum exclusions include several Schweingruber series, even though many Schweingruber series are used in MBH98. More


  1. John A.
    Posted Feb 23, 2005 at 5:53 PM | Permalink


    I’m not a statistician so I’m not sure I’m reading this correctly. What you appear to be saying is that some of the data series were deliberately filtered for “scatter” and decadal and centennial variation.

    What does that leave? I mean unless I’m missing something, why would Mann go to great lengths to remove the very variation that I would assume to be most interesting if you’re going to reproduce the variation of climate on a decadal and centennial scale? Also does this “aggressive standardization” have the effect of lowering the RE statistic and increasing the “skill” that Mann claimed?

    Does this step explain why the Hockey Stick is so straight and varies so little for 850 years?

  2. TCO
    Posted Sep 11, 2005 at 9:15 AM | Permalink

    Could you translate a bit more Steve? Are you worried that they are cooking the books? What sort of cooking?

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