How good is a group decision?

This paper studies a committee’s competency in making a correct judgement. Specifically, we examine how the committee’s competency compares with the average, median, lowest, and highest competencies of individual members. We propose novel measures for these comparisons and demonstrate that the lower and upper bounds of each committee member’s competency have distinct and significant effects on the committee’s overall competency. Furthermore, our research reveals an interesting relationship between the committee’s competency and the distribution of member competencies. We find that as the number of members with competencies higher than ½ increases, the likelihood of the committee’s competency surpassing that of individual members also increases. Conversely, when more members possess competencies lower than ½, the likelihood of the committee’s competency being lower than that of individual members also rises. To support this observation, we present theoretical findings from a comparison of the committee’s competency with the minimum and maximum competencies of its members. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.