Decisions with conflicting and imprecise information

Abstract

The most usual procedure when facing decisions in complex settings consists in consulting experts, aggregating the information they provide, and deciding on the basis of this aggregated information. We argue that such a procedure entails a substantial loss, insofar as it precludes the possibility to take into account simultaneously the decision maker's attitude towards conflict among experts and her attitude towards imprecision of information. We propose to consider directly how a decision maker behaves when using information coming from several sources. We give an axiomatic foundation for a decision criterion that allows to distinguish on a behavioral basis the decision maker's attitude towards imprecision and towards conflict.

Aggregation of multiple prior opinions

“…In terms of motivation and content, this paper is close to Gajdos and Vergnaud [15]. As mentioned above, they also deal with the aggregation of beliefs of uncertainty averse experts, and their suggested rule also takes the form suggested in (3).…”

“…First, Gajdos and Vergnaud [15] follow the set-up of Gajdos, Hayashi, Tallon and Vergnaud [14] in allowing sets of probabilities to be a component of the object of choice. Whereas Gajdos et al [14] deal with a single decision maker, who has a single set of probabilities, Gajdos and Vergnaud [15] deal with two experts and with two sets of probabilities, one for each expert. Thus, the decision maker has preferences over triples of the form (f, P , Q) where f is an act, P is the set of probabilities of the first expert, and Q -of the second.…”

“…Gajdos and Vergnaud [15] also deal with the aggregation of expert opinions under uncertainty. While their approach differs from ours in several significant ways (to be discussed below), they also axiomatize a functional of the form (3).…”

Setting Environmental Policy When Experts Disagree

“…This drop occurs because we assume that post-2030 funds represent the government's commitment to maintain the technological gains achieved by 2030. We 18 The analysis is carried out using the World Induced Technical Change Hybrid (WITCH) model (Bosetti et al [9]), an energy-economy-climate model that has been used extensively for economic analysis of climate change policies.…”

“…Later contributions by Gilboa and Schmeidler [22] (whose seminal paper dealt with the pure maxmin model), Ghirardato A1). The decision-theoretic literature has begun to address such imprecise probabilities (see, e.g., Gajdos et al [17] and Gajdos and Vergnaud [18]) in the context of decision making under ambiguity. Extending our framework to account for expert imprecision would be a very interesting avenue of future research.…”