Signal Detection Analysis of the Ideal Group

Abstract Theorems derived from the Theory of Signal Detectability are applied to the group decision problem. These theorems specify the behavior of the Ideal Group - the group having the highest achievable detection performance given an array of members with specified individual indices of detectability. Equations are provided for relating group performance to (1) the size of the group, (2) the detectability indices of the individual members, and (3) the correlation between member observations of the stimulus. The efficiency of real groups, such as juries and committees, is briefly discussed.