How to Make an Action Better

For two actions in a decision problem, a and b, each of which produces a state-dependent monetary reward, we study how to robustly make action a more attractive. Action a' improves upon a in this manner if the set of beliefs at which a is preferred to b is a subset of the set of beliefs at which a' is preferred to b, irrespective of the risk-averse agent's utility function (in money). We provide a full characterization of this relation and discuss applications in politics, bilateral trade, insurance, and information acquisition.