Comparison of Group Judgment Techniques with Short-Range Predictions and Almanac Questions

Abstract : An experiment designed to discover whether the results of laboratory studies dealing with general (almanac) information are relevant to the applied case when the true answer is unknown. Using short-range prediction questions as subject matter, the experiment indicates that, in general, Delphi procedures are at least as effective with short-range prediction as they have been for almanac material. Eight groups, of about 20 each, of upperclassmen and college graduates were given short-range prediction questions to answer in a 2-round Delphi exercise. Satisfactory answers were obtained for 32 of the 40 questions. Correlations between standard deviation and accuracy, and between group self- rating and accuracy, were significantly higher for the prediction than for the almanac questions. Half the groups generated estimates of the 3 quartiles of the distribution; the other half generated point estimates. No significant difference was observed between these two kinds of estimates.