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.