Combining forecasts: A philosophical basis and some current issues

A philosophical basis for combining forecasts and some important current issues in the area of combining forecasts are discussed briefly. The philosophical basis views forecasts as information and the combination of forecasts in terms of aggregation of information. The current issues involve the form of the combining rule, cases with agreement among forecasts, cases with extensive disagreement, dependence, uncertainty about forecast characteristics, instability in the forecasting process, robustness and the role of simple rules, and the role of group interaction.