Uniform expected utility criteria for decision making under ignorance or objective ambiguity

We provide an axiomatic characterization of a family of criteria for ranking completely uncertain and/or ambiguous decisions. A completely uncertain decision is described by the finite set of all its consequences. An ambiguous decision is described as a finite set of possible probability distributions over a finite set of prizes. Every criterion in the characterized family can be thought of as assigning to every consequence (probability distribution) of a decision an equal probability of occurrence and as comparing decisions on the basis of the expected utility of their consequences (probability distributions) for some utility function.

► The paper examines rankings of finite subsets of some universe.
► Subsets are interpreted as decisions with uncertain or ambiguous consequences.
► It axiomatically characterizes rankings based on the symmetric average utility.