The Global Warming Challenge

There are 19 forecasting principles that provide guidance on identifying, collecting, and preparing data to be used for forecasting. These principles include 3.3 Avoid biased data sources, 3.4 Use diverse sources of data, 4.1 Use unbiased and systematic procedures to collect data, 4.2 Ensure that information is reliable and that measurement error is low, 4.3 Ensure that the information is valid, 4.4 Obtain all of the important data, 4.6 Obtain the most recent data, 5.1 Clean the data, and 5.4 Adjust for unsystematic past events. While some of these principles at least may appear to be common sense, they are nevertheless often violated in practice with the consequence that forecasts are poor or even invalid. The Climate Audit site reports the findings of the often painstaking detective work required to determine whether the data used by climate scientists are consistent with these principles.