Elicitation of preferences under ambiguity

2011

Representing ambiguity in the laboratory using a Bingo Blower (which is transparent and not manipulable) and asking the subjects a series of allocation questions (which are more efficient than pairwise choice questions), we obtain data from which we can estimate by maximum likelihood methods (with explicit assumptions about the errors made by the subjects) a significant subset of the empirically relevant models of behaviour under ambiguity, and compare their relative explanatory and predictive abilities. Our results suggest that not all recent models of behaviour represent a major improvement in explanatory and predictive power, particularly the more theoretically sophisticated ones.

Handbook of Game Theory with Economic Applications, 2015

2009

Experimental work on preferences over risk has typically considered choices over a small number of discrete options, some of which involve no risk. Such experiments often demonstrate contradictions of standard expected utility theory. We reconsider this literature with a new preference elicitation device that allows a continuous choice space over only risky options. Our analysis assumes only that preferences depend on the probability p and prize x; U = u(p; x): We then allow subjects to choose p and x continuously on a linear budget constraint, r 1 p + r 2 x = m, so that all prospects with a nonzero expected value are risky. We test …ve of the most importantly debated questions about risk preferences: rationality, prospect theory asymmetry, the independence axiom, probability weighting, and constant relative risk aversion. Overall, we …nd that the expected utility model does unexpectedly well.

Journal of risk and uncertainty, 2010

In this paper we examine the performance of theories of decision making under uncertainty/ambiguity from the perspective of their descriptive and predictive power, taking into account the relative parsimony of the various theories. To this end, we employ an innovative experimental design which enables us to reproduce ambiguity in the laboratory in a transparent and non-probabilistic way. We find that judging theories on the basis of their theoretical appeal, or on their ability to do well in testing contexts, is not the same as judging them on the basis of their explanatory and predictive power. We also find that the more elegant theoretical models do not perform as well as simple rules of thumb.

Management Science, 2021

Experiments detecting ambiguity aversion often rely on the assumption that probabilities are exogenously given for some uncertain events. However, the canonical models that accommodate ambiguity into economic theory, such as the maxmin expected utility (MEU) and Choquet expected utility (CEU) models, are purely subjective. These models do not specify how subjects could incorporate exogenous probabilities into decisions. We study two approaches for embedding exogenous probabilities in the context of the thought experiments suggested by Mark Machina. We show that Machina’s choice behavior entails fundamentally different consequences for the ambiguity models mentioned; although it violates the CEU model, it is consistent with the MEU model. For the latter model, Machina’s experiments can test whether individuals adhere to expected utility for prospects whose consequences occur with the exogenously given probabilities. This paper was accepted by Manel Baucells, decision analysis.

In the last few decades, empirical studies of choice, probability assessment, and certainty equivalents have demonstrated that utilities are not independent of subjective probabilities. People are often pessimistic about the odds of a possible outcome if the outcome is bad. Rank-dependent theories and con®gural-weight theories can describe these interactions by allowing decision weights to vary with the rank orders of outcomes. Holding objective probability constant, lower-ranked outcomes typically receive greater weight than higher-ranked outcomes.

Economic Theory, 2011

This paper analyzes preferences in the presence of ambiguity that are rational in the sense of satisfying the classical ordering condition as well as monotonicity. Under technical conditions that are natural in an Anscombe-Aumann environment, we show that even for such general preference model it is possible to identify a set of priors, as first envisioned by . We then discuss ambiguity attitudes, as well as unambiguous acts and events, for the class of rational preferences we consider.

2015

In random–lottery incentive experiments, the choices of certain outcomes are stimulated by uncertain lotteries. This “certain–uncertain” inconsistency is evident, but only recently emphasized. Because of it, conclusions from a random–lottery incentive experiment that includes a certain outcome cannot be unquestionably correct. Well-known experimental results and purely mathematical theorems support this. The main result presented here is: The usual experimental systems of utility and prospect theories may need additional independent analyses in the context of the “certain–uncertain” inconsistency.

Mathematics of Operations Research, 2001

We introduce a general model of static choice under uncertainty, arguably the weakest model achieving a separation of cardinal utility and a unique representation of beliefs. Most of the non-expected utility models existing in the literature are special cases of it. Such separation is motivated by the view that tastes are constant, whereas beliefs change with new information. The model has a simple and natural axiomatization.

In the context of eliciting preferences for decision making under risk, we analyse the features of four different elicitation methods-pairwise choice, willingnessto-pay, willingness-to-accept, and the Becker-DeGroot-Marschak mechanism-and estimate noise, bias and risk attitudes for two different preference functionals, Expected Utility and Rank-Dependent Expected Utility. It is well-known that methods differ in terms of the bias in the elicitation; it is rather less well-known that methods differ in terms of their noisiness. It has also been reported that risk attitudes are not stable across different elicitation methods. Our results suggest that elicited preferences should only be used in the context in which they were elicited, and the bias in the certainty-equivalent methods should be kept in mind when making predictions based on the elicited preferences. Moreover, conclusions should be moderated to take into account the various methods' noise, which is generally lowest in the case of pairwise choice.