We present a model of information aggregation in which agents' information is represented through partitions over states of the world. We discuss three axioms, meet separability, upper unanimity, and non-imposition, and show that these three axioms characterize the class of oligarchic rules,...

We introduce an ordinal model of efficiency measurement. Our primitive is a notion of e ciency that is comparative, but not cardinal or absolute. In this framework, we postulate axioms that we believe an ordinal efficiency measure should satisfy. Primary among these are choice consistency and...

We introduce a theory of ranking sets of accomplishments in the presence of objectively incomparable marginal contributions (apples and oranges). Our theory recommends benchmarking, a method under which an individual is deemed more accomplished than another if and only if she has achieved more...

A planner wants to elicit information about an agent's preference relation, but not the entire ordering. Specifically, preferences are grouped into "types", and the planner only wants to elicit the agent's type. We first assume beliefs about randomization are subjective, and show that a space of...