The latest edition of the International Journal of Forecasting (2011, Vol 27, No. 1) in print is a 196 page Special Issue edited by George Wright and Gene Rowe on the important topic of judgmental forecasts by groups. Arguably, most important non-routine forecasts are made by groups of people combining their judgments in some way. The papers in the special issue provide evidence on how group judgmental forecasts can be improved. Topics include the effects on accuracy of diversity, role, aggregation, meetings, the Delphi technique, and prediction market. The papers can be found here.