Category Archives: Mann et al 2008

Gavin's Boast

Over the past few years, I’ve tried to keep an eye on and review new millennium proxies, posting a number of reviews on high-resolution ocean sediments and new tree ring proxies. I’ve reported on new tree ring data archived by Jacoby, Rob Wlson, David Meko, Connie Woodhouse and others, leading to some interesting interventions here […]

When the Team is on the Move

When the Team is on the move, they can sometimes move with surprising speed, as you’ll see in today’s story. Over the last month, we’ve seen multiple changes to the Mann SI, at first, without any notice. More recently, they’ve started to note the existence of changes, though, the changes themselves are typically not reported […]

How'd They Do That?

Take a look at today’s puzzle. On the left, I’ve plotted the three EIV reconstructions for the NH hemisphere using the infilled CRU series as a “target”. The data is straight from Mann’s website. One shows the “full” global network, one shows the “full” NH network (both of which I take to really be series […]

Off-center Butterworth Filters

Today I’m doing a first reconnaissance of Butterworth filters, used extensively in Mann et al 2008. The comments here are notes and thoughts and I hope that some issues can be clarified by readers. As of 12.30 pm today, I think that that the main problem that I’ve had pertains to a difference between R […]

The "Full" Network

The “full” network isn’t. Mann et al 2008 describe a “full” network consisting of 1209 proxies: We made use of a multiple proxy (‘‘multiproxy’) database consisting of a diverse (1,209) set of annually (1,158) and decadally (51) resolved proxy series … Reconstructions were performed based on both the ‘‘full’ proxy data network and on a […]

Code and realcode

Mann et al (PNAS 2008) states: All data used in this study and Matlab source codes for implementing the algorithms described, as well as additional supporting information are available at . They did make a much better effort than others in the field, but unfortunately the reality falls short of the PNAS representation. They […]

More on the MXD Data Set

On Sep 9, 2008, I sent an FOI request to the University of East Anglia, requesting a copy of the MXD data set as provided to Mann et al. Today (Oct 2, 2008), I was notified that they would provide this data and, sure enough the data is now posted (Oct 2, 2008) at […]

It’s Saturday Night Live

When you’re trading in puts and calls (or derivatives), it’s important to know the sign of the relationship between the value of the derivative and the market. Short positions will go up in value as the market goes down. And, unfortunately, you don’t get to decide afterwards whether you wanted to be short or long. […]

Mann et al 2008 and GAAP Accounting

Let’s say that you were a partner of the firm North, Hegerl and Cicerone and charged with issuing an opinion on the financial statements of Team Capital Management Inc.(TCM) And let’s say that you were doing so in heady pre-crash days when markets were going up and mark-to-market accounting was something that the companies wanted […]

The MBH98 Corrigendum

The SI for MBH98 listed 34 tree ring series that were not actually used. This was acknowledged in their 2004 Corrigendum which provided the following implausible excuse: These series, all of which come from the International Tree Ring Data Bank (ITRDB), met all the tests used for screening of the ITRDB data used in ref. […]


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