Choice and Opportunity Costs
定义了选择的机会成本，并构建了一个内省均衡模型，其中选择与成本相互影响，导致非标准行为如不可传递选择，且最大化效用不能直接解释为福利相关的显示偏好。
Abstract We define the (physical) opportunity cost of a choice x as the alternative that would be chosen if x were not available, and the opportunity cost of any unchosen alternative as x itself. The agent has preferences over pairs consisting of alternatives and their opportunity costs. Because costs affect choice and vice-versa, choice results from an intrapersonal equilibrium rather than from simple maximisation. In spite of significant rationality assumptions, the resulting behaviour can be highly non-standard, allowing intransitive choices. Rational utility maximisation is ensured by an additional new consistency condition on preferences. However, we argue that the maximised utility cannot be straightforwardly interpreted as a welfare relevant “revealed preference”. A generalisation of our model accommodates additional departures from standard rationality in the form of menu effects.