Tag Archives: preisendorfer

Richard Smith on PC Retention

Richard Smith, a prominent statistician, has recently taken an interest in multiproxy reconstructions, publishing a comment on Li, Nychka and Ammann 2010 (JASA) here and submitting another article here. I’ll try to comment more on another occasion. Today I want to express my frustration at the amount of ingenuity expended by academics on more and […]

Gavin and the PC Stories

How many principal components to retain? Recent readers of Climate Audit may not realize that this was an absolute battleground issue of MBH and Wahl and Ammann. In one sense, it was never resolved with MBH back in 2003-2005, but that was before the existence of blogs made it possible to focus attention on problems. […]

Rule N and Weighted Regression

Today’s post, which has a forbidding title, contains an interesting mathematical and statistical point which illuminates the controversy over how many PCs to retain. In my re-visiting the totally unknown corner of Mannian methodology – regression weights and their determination – I re-parsed the source code, finding something new and unexpected in Mannian methodology and […]

A Challenge to Tamino: MBH PC Retention Rules

Today I wish to re-visit an issue discussed in one of the very first CA posts: did MBH98 actually use the PC retention rules first published in 2004 at realclimate here and described both there and by Tamino as “standard” selection rules. Much of the rhetorical umbrage in Tamino’s post is derived from our alleged […]

"Mannian" PCA Revisited #1

One of Hansen’s pit bulls, Tamino, has re-visited Mannian principal components. Tamino is a bright person, whose remarks are all too often marred by the pit bull persona that he has unfortunately chosen to adopt. His choice of topic is a curious one, as he ends up re-opening a few old scabs, none of which […]

More Tangled Webs

Here’s something amusing. Mann has written to the House Energy and Commerce Committee, arguing that we made a fundamental and obvious mistake in how we calculated AR1 coefficients for the North American tree ring network, which exaggerated the HS-ness of the simulated hockey sticks – a mistake that Ritson has now supposedly picked up and […]

Huybers #2: Re-Scaling

Huybers’ second and more interesting (to me) issue pertains to the benchmarking of the RE statistic.I’m going to start in the middle of this issue. If I start with the history e.g. defining the RE statistic and showing its history (and I just tried), it’s hard to get to the punch line. So what I’m […]

Roll Over, Preisendorfer

I think that Preisendorfer would roll over in his grave if he saw how Ammann, Schmidt and Mann were bastardizing his Rule N.

Source Code: Preisendorfer’s Rule N

Here’s a comment on handling of Preisendorfer’s Rule N in the code dump; I’ll post some further comments on Preisendorfer on Preisendorfer’s Rule N in a few days. There is NO source code showing the application of Preisendorfer’s Rule N to tree ring networks – a battleground issue, if you will. There is some source […]

MBH98 Source Code: Status Report

I reported recently on that the recently archived (July 2005) source code multiproxy.f shows that the cross-validation R2 statistic was calculated and not reported. Today, I’m merely going to summarize some collation details from my inspection of the code, listing input files, output files and providing a lexicon of variables. The source code requires a […]