Tag Archives: verification r2

Verification r2 Revealed!!!

For the first time, a member of the Hockey Team (Ammann and Wahl) has admitted that the verification r2 for the early steps of MBH98 are catastrophic. Results confirm our calculations – as we predicted. They have not explained the justification for issuing a press release that all our claims were "unfounded" and UCAR has […]

MBH98 and Correlation

One more bit of review before we get to Ammann’s answer. As an excuse for not answering the request of the House Energy and Commerce Committee about the R2 statistic, Mann told them that his "colleagues and [himself] did not rely on this statistic" in the following terms: The Committee inquires about the calculation of […]

More on MBH98 Cross-Validation R2

I have previously discussed here and here Mann’s answer to the following question from the House Committee: "7 c. Did you calculate the R2 statistic for the temperature reconstruction, particularly for the 15th Century proxy record calculations and what were the results?" Mann stated: "My colleagues and I did not rely on this statistic in […]

Cross-Validation R2 Source Code Reference

Just for reference: here’s the code excerpt where Mann calculates the cross-validation R2 statistics and then writes it to file. You can see the original code at ftp://holocene.evsc.virginia.edu/pub/MANNETAL98/METHODS/multiproxy.f.{Update – http://www.meteo.psu.edu/holocene/public_html/shared/research/MANNETAL98/METHODS/multiproxy.f ] Search down using corrnhem or verif1,out. There is no "if" as to whether he calculated the cross-validation R2 statistic.

MBH98 Source Code: Cross-validation R2

Mann has just(July 2005) archived a fortran program at ftp://holocene.evsc.virginia.edu/pub/MANNETAL98/METHODS/multiproxy.f. {Update: see here] Here are my first thoughts on this.

Cook et al. [2004]

What is ironic in Mann’s citation of Cook as authority that paleoclimatologists need not provide a range of verification statistics is that Cook et al. [2004] actually provide a suite of verification statistics, headed by the R2 statistic, which Mann et al. now object to.

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