On rationalizability of choice functions: A characterization of the median

Abstract.

In this paper we characterize choice behaviour that picks the median element from a set of feasible alternatives. It is easily seen that this choice behaviour violates most of the standard consistency conditions for set contraction and set expansion. The paper offers a complete characterization in terms of pure choice function conditions, and contrasts the new axiom set with the traditional consistency conditions. It also suggests alternative external references which could explain the choice of the median.