Prices vs. Quantities: The Irrelevance of Irreversibility *

Abstract We explore the efficacy of price and quantity controls in a dynamic setup in which the decisions of some agents are irreversible. The assumption of irreversibility is shown to improve the performance of a tax relative to that of a system of tradable quotas and significantly alter the equilibrium behavior of agents. We nevertheless conclude that taking into account the fact that agents’ decisions may be irreversible does not lead to policy implications significantly different from those reached in a simpler model in which irreversibility is ignored.