Category Archives: Statistics

Smerdon et al 2008 on RegEM

Smerdon et al 2008 is an interesting article on RegEM, continuing a series of exchanges between Smerdon and the Mann group that has been going on for a couple of years. We haven’t spent much time here on RegEM as we might have. I did a short note in Nov 2007 here. In July and […]

More on Voodoo Correlations

Mann said: Although 484 (~40%) pass the temperature screening process over the full (1850–1995) calibration interval, one would expect that no more than ~150 (13%) of the proxy series would pass the screening procedure described above by chance alone. Reader DC said: Of the 484 proxies passing the 1850-1995 significance test, 342 also passed both […]

Mann and Perfect Reconstructions

I finally turned over a few stones in Mann’s EIV reconstructions, little suspecting the perfection that awaited me in the cave using the simple and unassuming alter ego shglfulihad_smxx. The figure below compares the SH reconstruction to the smoothed (SH) iHAD instrumental version. From the frail instruments of speleothems, bristlecone ring widths and upside-down sediments, […]

This Gets Even More Amusing

Can anyone on the Team actually hit a target? A couple of days ago, I reported that Santer’s own method yielded failed t-tests on UAH when data up to 2008 (or even 2007) was used. I also reported that their SI (carried out in 2008) included a sensitivity test on their H1 hypothesis up to […]

The Santer "S.D."

Lucia has written an interesting post – see here, continuing the effort to figure out the Santer brainteaser. I can shed a little more light (I think) on what Santer’s “S.D” is in operational terms. I was able to replicate Santer’s Table III values using the line item from Table 1 entitled “Inter-model_S.D._T2LT” which is […]

Does the Endpoint of Santer H2 "Matter"?

Yes. Perhaps the first thing that I noticed about this article was the endpoint for analysis of 1999 – this seemed very odd. I mentioned that a Santer coauthor wrote to me, saying that the endpoint didn’t matter relative to the Douglass endpoint of 2004. That turns out to be true, but why would anyone […]

Lucia on Santer

Excellent post here. Please comment at Lucia’s.

Ian Jolliffe Comments at Tamino

Ian Jolliffe, a noted principal components authority, has posted a comment at Tamino’s, which repudiates Tamino’s (and Mann’s) citation of Jolliffe as a supposed authority for Mannian PCA. He wrote to me separately, notifying me of the posting and authorizing me to cross-post his comment and stating that we had correctly understood and described his […]

Pielke Jr discusses the Bishop and the Stick

Roger Pielke Jr has written a gracious post , following up on Bishop Hill’s post and considering the issues as they pertain to science policy, and, in particular, the processes of peer review and due diligence, which have informed many of my posts. He refers to and reconsiders a post that I wrote for Prometheus […]

Caspar Ammann, Texas Sharpshooter

The Texas Sharpshooter fallacy is a logical fallacy where a man shoots a barn thirty times then circles the bullet holes nearest each other after the fact calling that his target. It’s of particular concern in epidemiology. Folks, you are never going to see a better example of the Texas Sharpshooter work itself out in […]