Abstract In decision situations where relevant variables cannot be easily measured, mathematical aggregation of individual judgments may prove to be a useful decision aid. A wide variety of studies indicate that composite judgments formed by equal-weighting aggregation models outperform the average individual judge making up the composite. However, the use of these composite judgments in actual decision making situations has not been suggested because of inefficiencies caused by the need to include the judgments of a large number of individuals in the formation of the composite. If composites formed by pooling judgments of fewer decision makers produce similar incremental performance, these inefficiencies would be substantially reduced, making use of such a technique more practical. This study empirically tested the effects of group size upon the incremental accuracy of an equal-weighted composite judge in three different judgment tasks. The results indicate that on average the majority of the increment gained by aggregating large numbers of judges can be obtained by aggregating three judges.