A short list for prediction making of groups (and via extension decision making):
http://en.wikipedia.org/wiki/Prediction_market
http://en.wikipedia.org/wiki/Delphi_method
http://en.wikipedia.org/wiki/Wideband_delphi
http://en.wikipedia.org/wiki/Planning_poker
http://en.wikipedia.org/wiki/Statistical_survey
A short list for prediction making of groups (and via extension decision making):
http://en.wikipedia.org/wiki/Prediction_market
http://en.wikipedia.org/wiki/Delphi_method
http://en.wikipedia.org/wiki/Wideband_delphi
http://en.wikipedia.org/wiki/Planning_poker
http://en.wikipedia.org/wiki/Statistical_survey