This is the final instalment in a series of posts documenting dubious scholarship and unattributed sources in the background chapter of the touchstone of climate contrarians known as the Wegman Report. That report has been touted as Exhibit A proving the “destruction” of Michael Mann’s “hockey stick” graph by self-styled climate auditor Steve McIntyre.
Previously, I found extensive passages bearing “striking similarity” to a classic text by the distinguished paleoclimatologist (and “hockey stick” co-author) Raymond Bradley in the background sections on tree rings and on ice cores. Subsequently, the background section on social networks was found to contain material apparently drawn without attribution from a variety of sources, including Wikipedia and several text books.
This time, I’m looking at section 2.2 (see Wegman Report PDF at p. 15), which gives the background of key statistical concepts, including Principal Component Analysis. Astonishingly, even this section appears to contain a significant amount of unattributed material from other sources, although quite a bit less than the other sections. Again, Wikipedia appears to be a key source, along with a couple of text books.
I’ll also introduce some refinements to the text analysis, based largely on John Mashey’s recent innovations. Those refinements allow a better characterization of the relationship between various passages in Wegman et al and their apparent antecedents, as well as permitting a quantitative analysis based on word counts.