A Measure of Instability for Matchings in Marriage Markets

Abstract: In marriage markets (two-sided one-to-one matching problems) the number of blocking pairs which exist against a matching is often used as a measure of instability. We argue that in many cases this measure is economically implausible. To fix the problem, we state two principles which should be fulfilled by sets of blocking pairs whose cardinalities are taken as measures of instability. We offer economic interpretations both of these principles and of the corresponding sets. Furthermore, we show how to compute these sets and prove some results which are relevant for a workable measure of instability. 1