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In decision theory, subjective expected utility is the attractiveness of an economic opportunity as perceived by a decision-maker in the presence of risk. Characterizing the behavior of decision-makers as using subjective expected utility was promoted and axiomatized by L. J. Savage in 1954〔Savage, Leonard J. 1954. ''The Foundations of Statistics''. New York, Wiley.〕 〔Karni, Edi. "Savage's subjective expected utility model." The New Palgrave Dictionary of Economics. Second Edition. Eds. Steven N. Durlauf and Lawrence E. Blume. Palgrave Macmillan, 2008. The New Palgrave Dictionary of Economics Online. Palgrave Macmillan. 23 August 2014 Savage proved that, if the decision-maker adheres to axioms of rationality, believing an uncertain event has possible outcomes each with a utility of then the person's choices can be explained as arising from this utility function combined with the subjective belief that there is a probability of each outcome, The subjective expected utility is the resulting expected value of the utility, : If instead of choosing the person were to choose the person's subjective expected utility would be : Which decision the person prefers depends on which subjective expected utility is higher. Different people may make different decisions because they may have different utility functions or different beliefs about the probabilities of different outcomes. Savage assumed that it is possible to take convex combinations of decisions and that preferences would be preserved. So if a person prefers to and to then that person will prefer to , for any . Experiments have shown that many individuals do not behave in a manner consistent with Savage's axioms of subjective expected utility, e.g. most prominently Allais (1953) and Ellsberg (1961). == Notes == 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Subjective expected utility」の詳細全文を読む スポンサード リンク
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