Tag Archives: r2

Replication Problems: Mannian Verification Stats

If anyone feels like sticking needles in their eyes, I’d appreciate assistance in trying to figure out Mannian verification statistics. Even when Mann posts up his code, replication is never easy since they never bothered to ensure that the frigging code works. Or maybe they checked to see that it didn’t work. UC’s first post […]

Emile-Geay and Verification r2 Statistics

Julien Emile-Geay from Judith Curry’s university – who, together with Kim Cobb, is teaching a course on the Hockey Stick – has joined our debate with a forceful criticism of Craig Loehle’s recent paper. While Emile-Geay seems to be a lively young man with some very cordial comments about CA here and his comments are […]

Benchmarking from VZ Pseudoproxies

Von Storch et al 2004 advocated using climate models to generate pseudoproxies to test the properties of proposed multivariate methods. Hardly unreasonable. I might argue that these are long-winded ways of generating proxy series with certain kinds of temporal and spatial covariance structures, but there’s much to be said for testing methods on some standard […]

M&M at the NAS Panel

Back to reporting on our presentation to the NAS panel, after which I’ll report on Mann. We presented last in the day, immediately following von Storch. Hughes and Mann presented on Friday morning. We gave them a long written presentation, and touched the high points in our PPT, also providing them with a CD of […]

Wahl and Ammann – July 2005 Review

I’m posting up our July 2005 review of Wahl and Ammann. The recently accepted version is here. I’m posting this up for a variety of reasons. Mann relied heavily on Wahl and Ammann in his NAS panel testimony (which wasn’t even online as accepted last week) and so it’s hard to finish off the discussion […]

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 […]

Ammann at AGU #2

I’m going to give a fairly brief account of previous attempts to get the residual series and/or cross-validation R2 from Mann, including inquiries to Mann, N.S.F., through Nature, by Climatic Change, by Natuurwetenschap & Techniek and by the House Energy and Commerce Committee. As you will see, no one has been able to get Mann […]

Mann and Rutherford [2002]: the CE Statistic

Barton’s question 7d asked MBH about other verification statistics. We’ve discussed their withholding of the R2 statistic here, here and here. In our GRL article, we also pointed out that their 15th century reconstruction also failed the CE statistic, another verification statistic used in dendroclimatic studies [Cook et al, 1994]. Mann’s retort was that climatologists […]

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 […]

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.