The position at ClimateAudit is that error bars in MBH98 are incorrectly calculated and “pseudo science” and that no one knows how the error bars in MBH99 were calculated (not just Me, Jean S, UC but also von Storch) and these error bars are also “pseudo science”. Notwithstanding this view, UC has posted up MBH98-style […]

Update: the following does not explain the Caramilk secret of MBH99 confidence intervals, which remains unexplained and mysterious. End Update. OK, Mann starts with a sigma obtained from the standard errors in the calibration period from his hugely overfitted model. He uses this in MBH98. In MBH99, recognizing the autocorrelation in the residuals, he adjusts […]

I’ve posted in the past on the mystery of MBH confidence interval calculations, especially the mysterious MBH99 confidence intervals (another Caramilk secret). In our NAS panel presentation and perhaps before, I’d speculated that MBH98 confidence intervals, rotundly described in MBH98 as “self-consistently estimated” were nothing other than twice the standard error of the (overfitted) calibration […]

I’m working away at Jones et al [1998]. Here’s an interesting diagram from Jones et al [Science, 2001] , which purports to provide confidence intervals for the J98 reconstruction (blue). There’s (at least) one really strange feature in this diagram. See if you can pick it out. Original Caption: Fig. 2. (A) Northern Hemisphere surface […]

At present, I’m having trouble figuring out what on earth is going on with MBH confidence intervals. Here is a figure showing the one-sigma confidence intervals in MBH98 (cyan) and MBH99 (salmon). Figure 1. MBH98 and MBH99 one-sigma by calculation step. Cyan – MBH98; salmon – MBH99. Solid black – CRU std dev; dashed red […]

I’ve been looking at MBH98 confidence interval estimation. There are many puzzles as to methodology. Here I’ll touch on some archiving oddities. Figure 1. Standard deviation of MBH98 Reconstruction Steps

In my post on Tornetrask showing the impact of the Briffa-Jones "adjustment", I didn’t comment on confidence intervals.