DP12492 On the Optimal Majority Rule
We develop a simple model that rationalizes why less stringent majority rules are preferable to unanimity in large committees. Proposals are
randomly generated and the running proposal is adopted whenever it is approved by a sufficiently large share of voters. Unanimity induces excessive delays while too weak majority requirements induce the adoption of suboptimal proposals. The optimal majority rule balances these two inefficiencies: it requires the approval by a share equal to the probability (assumed to be constant across proposals) that a given member gets more than the average welfare associated with the running proposal. Various extensions are considered.