Superforecasting: The Art and Science of Prediction

by Philip E. Tetlock

separating the predictable from the unpredictable is difficult work. There’s no way around it. Meteorologists know that better than anyone. They make large numbers of forecasts and routinely check their accuracy—which is why we know that one-and two-day forecasts are typically quite accurate while eight-day forecasts are not. With these analyses, meteorologists are able to sharpen their understanding of how weather works and tweak their models. Then they try again. Forecast, measure, revise. Repeat. It’s a never-ending process of incremental improvement that explains why weather forecasts are good and slowly getting better. There may be limits to such improvements, however, because weather is the textbook illustration of nonlinearity. The further out the forecaster tries to look, the more opportunity there is for chaos to flap its butterfly wings and blow away expectations.