Armstrong and Green estimated that the IPCC report violated 72 of 89 forecasting principles they were able to rate (their list of forecasting principles includes 140 principles, but they judged only 127 as applicable to climate forecasting, and were able to rate only 89 of them)

When I read this, I thought, "who ever fulfills 140 principles for anything?" but it turns out the list is largely sensible.

So that's not really why I'm commenting. I'm commenting because sensible list or not, their application of it is hilarious. Also, for further examples of how the authors have no axe to grind, see their veiled thrusts at the climatologists who snubbed them :P

Selected principles of forecasting "clearly" violated by the IPCC (from Armstrong and Green 2007):

Prior to forecasting, agree on actions to take assuming different possible forecasts.
Make sure forecasts are independent of politics.
Consider whether the events or series can be forecasted.
Ensure that the information is valid. (Manfred - Whoops! Forgot all about that one!)
Examine the value of alternative forecasting methods.
Shrink the forecasts of change if there is high uncertainty for predictions of the explanatory variables. (Manfred - Not sure if this is how uncertainty works)
Use trimmed means, medians, or modes.
Compare reasonable methods.
Test the client’s understanding of the methods. (Manfred - Good luck!)
Examine all important criteria.
Assess face validity.
Tests of statistical significance should not be used.
Present forecasts and supporting data in a simple and understandable form. (Manfred - Oh snap!)

I wonder how they evaluated whether the IPCC "assessed face validity." Were they just expecting a paragraph subtitled "Assessing Face Validity," like a bad 10th grade lab report? Or did they sleuth it out, only concluding after extensive background checks, "these guys couldn't assess face validity if it was biting them in the face very validly. F minus minus."