Safety, in Numbers

Abstract: We introduce a way to compare actions in decision problems. An action is safer than another if the set of beliefs at which the decision-maker prefers the safer action increases in size (in the set inclusion sense) as the decision-maker becomes more risk averse. We provide a full characterization of this relation and show that it is equivalent to a robust concept of single-crossing. We discuss applications to investment hedging, security design, and game theory.