Condorcet efficiency is a measurement of the performance of voting methods.
[2][3][4] A voting method with 100% efficiency would always pick the Condorcet winner, when one exists, and a method that never chose the Condorcet winner would have 0% efficiency.
[1] It was initially developed in 1984 by Samuel Merrill III, along with social utility efficiency.
[1] A related, generalized measure is Smith efficiency, which measures how often a voting method elects a candidate in the Smith set.
[citation needed] Smith efficiency can be used to differentiate between voting methods across all elections, because unlike the Condorcet winner, the Smith set always exists.