Theoretical Economics, Volume 17, Number 2 (May 2022)

Theoretical Economics 17 (2022), 507–519


What were you thinking? Decision theory as coherence test

Itzhak Gilboa, Larry Samuelson

Abstract


Decision theory can be used to test the logic of decision making---one may ask whether a given set of decisions can be justified by a decision-theoretic model. Indeed, in principal-agent settings, such justifications may be required---a manager of an investment fund may be asked what beliefs she used when valuing assets and a government may be asked whether a portfolio of rules and regulations is coherent. In this paper we ask which collections of uncertain-act evaluations can be simultaneously justified under the maxmin expected utility criterion by a single set of probabilities. We draw connections to the the Fundamental Theorem of Finance (for the special case of a Bayesian agent) and revealed-preference results.

Keywords: Decision theory, revealed preference, coherence, maxmin expected utility

JEL classification: D8

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