Iridge versus TTLS. What if a key text on this conundrum of the day resided in an anonymous open peer review? Would we, within the ethical standards of modern climate science, be entitled to speculate on the identity of the author of these pearls? Or would that be an ethical violation “as bad as possible”? […]

Many CA readers know a lot about regression and quite a bit about principal components, but I dare say that a much fewer number are familiar with Truncated Total Least Squares (to which the regpar parameter belongs.) We’re seeing interesting interactions between PC=k and regpar=r – and there is little, if anything, in regular statistical […]

I’ve now ported my emulation of Schneider’s RegEM PTTLS to R and benchmarked it against Jeff’s Matlab as shown below. I caution readers that this is just an algorithm. There are other ways of doing regressions and infills. The apparent convergence to three PCs noted by Roman is still pending as a highly interesting phenomenon. […]

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 […]

Mann et al 2007 is a new RegEM version, replacing the RegEM calculations of Rutherford et al 2005. The logic is not entirely self-contained and so I re-visited some of our previous comments on Rutherford et al here here here here . I’m going to reprise two issues today: Collation Errors, a small but amusing […]

I realize that not all CA readers are interested in multivariate methods and that dendroclimatologists want to “forget the math”, but I find it interesting to try to relate dendro and paleoclimate recipes to known statistical methodologies that you can read about in texts. I commented the other day on the form of Principal Components […]

RegEM has reared its ugly head again in Mann’s review of Burger and Cubasch.