Category Archives: Replication

MBH-style Tests for Normality and Whiteness

MBH98 and subsequent Mannian papers (MBH99, Rutherford et al , 2005) report briefly that they tested calibration residuals (not verification residuals) for normality and whiteness. These results are used to calculate confidence intervals. They do not use typical tests for whiteness e.g. Ljung-Box portmanteau statistic used not just in econometrics, but also in climate e.g. […]

Source Code: Preisendorfer’s Rule N

Here’s a comment on handling of Preisendorfer’s Rule N in the code dump; I’ll post some further comments on Preisendorfer on Preisendorfer’s Rule N in a few days. There is NO source code showing the application of Preisendorfer’s Rule N to tree ring networks – a battleground issue, if you will. There is some source […]

A Summary of MBH98 Replication Issues

Mann and realclimate have argued that MBH98 was replicable on the original record. Mann cites Wahl and Ammann as support for this, but Wahl and Ammann are close associates of Mann’s (Ammann is a realclimate contributor), working recently from a much different record, hardly "independent" and their code only addresses one area of MBH98 calculations. […]

Wahl and Ammann: Some Verification Statistics

I’m now completely file compatible with Wahl and Ammann. In terms of my algorithm, I had to tweak the procedure for scaling RPCs a little, but the RPCs themselves were identical. It took some patience to reconcile differing data setups. I archived results from a complete run-through from their base case a couple of days […]

Wahl and Amman: More

I’ve done a complete run using the WA basecase using the Windows-modified script that I archived a couple of days ago. From the output of this run, I extracted the results of the AD1400 step and made a stepwise splice, which I’ve saved here together with the MBH98 stepwise reconstruction. This may be of interest […]

Wahl-Ammann: More Early Returns

As I discussed previously here, I had been able to quite accurately replicate Mann’s temperature principal components (the first 16 of which have been archived for a long time). Notwithstanding that these calculations can actually be replicated quite accurately, Wahl and Ammann calculated new reference temperature PCs using annual data on the basis that they […]

MBH Confidence Intervals #2

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 […]

MBH98 Confidence Intervals

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

Pacific Research

The “Index of Leading Environmental Indicators 2005” of the Pacific Research Institute says the following: “The “hockey-stick” graph, believed to be one of the leading indicators of global warming, is now being called “rubbish.” Scientists have shown that the graph’s underlying equation would generate the same result for any series of random numbers." In another […]

Federal Reserve Bank Working Paper on Replication

Richard G. Anderson, William H. Greene, Bruce D. McCullough and H. D. Vinod have some very interesting comments in a recent Federal Reserve Bank of St Louis Working Paper about the importance of archiving data and code, in which they cite our work approvingly. Here’s a nice cut phrase that they quote: An applied economics […]