A new article by Kesten Green and Scott Armstrong presents evidence that complexity increases forecast error. Have they missed any evidence that might challenge that conclusion?

Their article, "Simple Forecasting: Avoid Tears Before Bedtime" proposes that simplicity in forecasting requires (1) method, (2) representation of cumulative knowledge, (3) relationships in models, and (4) relationships among models, forecasts, and decisions are all sufficiently uncomplicated as to be easily understood by decision makers. Their review of studies comparing simple and complex methods has found 93 comparisons in 28 papers. Complexity beyond the sophisticatedly simple failed to improve accuracy in all of the studies and increased forecast error by an average of 32 percent in 21 studies with quantitative comparisons. 

The effects are so consistent and substantial that the authors are concerned that they might have overlooked disconfirming evidence. If you know this area, please look at the references in the paper to see if they have overlooked any key studies, and send your suggestions to  This email address is being protected from spambots. You need JavaScript enabled to view it. . The paper is available on the simple-forecasting.com page. 

The call for papers has been issued for the 35th International Symposium on Forecasting. The Symposium will be held in Riverside, California from June 21 to 24, 2015. The deadline for abstract submissions is 16 March 2015. Proposals for invited sessions are due by 31 January. For more information, go to the ISF 2015 submissions page, here.

For the twelfth year, the International Institute of Forecasters, in collaboration with SAS®, is proud to announce financial support for research on how to improve forecasting methods and business forecasting practice. The award for this year will be two $5,000 grants. The application deadline for the grant year 2014-2015 is September 30, 2014. For more information visit the IIF website, here.

Springer has now made Principles of Forecasting: A Handbook for Researchers and Practitioners available for sale in the form of single chapters. Purchase chapters from the Singer site, here.

The Golden Rule of Forecasting is to "be conservative" in the sense of adhering to cumulative knowledge. The Rule can be implemented by following 28 operational guidelines, based on cumulative knowledge about forecasting, in the form of a Checklist. The Golden Rule applies to all areas of forecasting. We will introduce The Golden Rule Checklist software at the International Symposium of Forecasting in Rotterdam on June 30.

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Principle of the day:

14.13-Incorporate the uncertainty associated with the prediction of the explanatory variables in the prediction intervals

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