Tag Archives: screening

More on Screening in Gergis et al 2012

First, let’s give Gergis, Karoly and coauthors some props for conceding that there was a problem with their article and trying to fix it. Think of the things that they didn’t do. They didn’t arrange for a realclimate hit piece, sneering at the critics and saying Nyah, nyah, what about the hockey stick that Oerlemans […]

Gergis “Significance”

Jean S observed in comments to another thread that he was unable to replicate the claimed “significant” correlation for many, if not, most of the 27 Gergis “significant” proxies. See his comments here  here Jean S had observed: Steve, Roman, or somebody ;) , what am I doing wrong here? I tried to check the […]

Myles Allen Calls For “Name and Shame”

Myles Allen, a declared supporter of open data archives, has, in blog comments here, proposed “name and shame” as a first tactic against data obstructionists (as opposed to FOI). Journal editors can and should enforce a simple “disclose or retract” policy if a result is challenged, and almost all of them do: if any don’t, […]

More on Voodoo Correlations

Mann said: Although 484 (~40%) pass the temperature screening process over the full (1850–1995) calibration interval, one would expect that no more than ~150 (13%) of the proxy series would pass the screening procedure described above by chance alone. Reader DC said: Of the 484 proxies passing the 1850-1995 significance test, 342 also passed both […]

The Mann Correlation Mystery

Here’s another interesting mystery in Mann et al 2008. Their SI table rtable1209 reports correlations to 1850-1995 instrumental temperature. The correlations reported in their PNAS SI Table SD1 sets all but 484 “significant” values to NA, so the r1209 table is more comprehensive. The instrumental version supposedly used in their calculations is now archived at […]

Proxy Screening by Correlation

I’ve made histograms of reported proxy correlations for 1850-1995, as reported in r1209.xls (which contains results for all proxies, unlike SI SD1.xls which withholds results below a benchmark.) The breaks are in 0.1 intervals. On the left is the histogram before screening; on the right, a histogram of the 484 proxies after screening.     […]

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