downweighting

The various methodological permutations and combinations equate to upweighting and downweighting of bristlecones but that was something that we learned in the course of the replication effort.

Juckes and Covariance PCs « Climate Audit 2006

All that happens is downweighting of bristlcones – for which realclimate and Juckes use the code word “much of the data” – they never use the word “birstlecone” in this context.

Juckes and Covariance PCs « Climate Audit 2006

The only data whose downweighting is material are the bristlecones.

Q.e.d. « Climate Audit 2006

PC methods are extraordinarily “non-robust” in a statistical sense in that they preserve contaminants for a regression as distinct entities rather than downweighting them.

Trip Report – Holland « Climate Audit 2006

One point that Wahl and Ammann and ourselves agree on, but which Juckes appears to contest, is that principal components methodologies applied to AD1400 MBH98 networks result in upweighting or downweighting of bristlecones.

2006 November « Climate Audit 2006

One point that Wahl and Ammann and ourselves agree on, but which Juckes appears to contest, is that principal components methodologies applied to AD1400 MBH98 networks result in upweighting or downweighting of bristlecones.

Q.e.d. « Climate Audit 2006

We can categorically say that we did not select a PC methodology with a view to downweighting bristlecones; it was only through patient detective work that we learned of the effect of bristlecones.

Juckes and Covariance PCs « Climate Audit 2006

PC methods are extraordinarily “non-robust” in a statistical sense in that they preserve contaminants for a regression as distinct entities rather than downweighting them.

Trip Report – Holland « Climate Audit 2006

It turned out that about 35 series said to have been used were not actually used, but of course this “didn’t matter”, whereas not using the bristlecones or downweighting the bristlecones was “throwing out data”.

MBH98 Figure 7 Unveiled « Climate Audit 2006

In an unguarded moment, Wahl and Ammann 2006 admitted that the downweighting from use of covariance PCs is precisely equivalent to bristlecone downweighting – I’ve got a pretty graphic in my Stockholm/Holland presentation illustrating this.

Juckes and Covariance PCs « Climate Audit 2006