Voting Systems, Honest Preferences and Pareto Optimality

Abstract

The market is a decentralized system that can bring about efficient economic decisions. This paper examines whether social choice mechanisms can duplicate this success in the political arena. The famed Arrow result tells us centralized systems cannot achieve efficient, nondictatorial outcomes unless they rely on cardinal preferences. With decentralization, efficiency comes to require something more: the truthful revelation of preferences. Schemes that elicit honest preferences are derived here. By their very structure they are shown to lead to inefficient outcomes. This negative result leads to the question whether the validity of the initial analogy continues. Market-based standards of performance may be innappropriate for investigations of political phenomena.