This paper suggests that decision-making under uncertainty is, at leas
t partly, case-based. We propose a model in which cases are primitive,
and provide a simple axiomatization of a decision role that chooses a
''best'' ad based on its past performance in similar cases. Each act
is evaluated by the sum of the utility levels that resulted from using
this act in past cases, each weighted by the similarity of that past
case to the problem at hand. The formal model of case-based decision t
heory naturally gives rise to the notions of satisficing decisions and
aspiration levels.