Afriat's Theorem and some Extensions to Choice under Uncertainty*

The first part of the article reviews the methodology developed by Sydney Afriat for determining whether a finite set of price and quantity data are consistent with utility maximising behaviour by a consumer. Some extensions of his basic model to models of consumer behaviour where the structure of preferences is restricted in some way are also explained. Examples of special structures are homotheticity, separability and quasi-linearity of the utility function. The second half of the article is devoted to developing Afriat-type consistency tests for expected and non-expected utility maximising behaviour.