Group Decision

Abstract

AbstractThe practice of risk assessment depends heavily on insights from the theory of the individual decision maker, both normative and behavioral. However, most risk related decisions impact on, and involve, multiple parties who may have interests which are not congruent. This article considers what light normative and behavioral theories of group decision can shed on risk assessment problems.This article reviews ideas from game theory, such as the Nash equilibrium and the Nash bargaining solution, and relates them to a nuclear‐waste management example. Key ideas from the theory of social choice, such as Arrow's Paradox and Sen's Impossibility of a Paretian Liberal are also discussed. Alongside this normative theory, some of the key findings from the social psychological literature about how preferences are formed in groups are also described, focusing particularly on theories of social influence and phenomena such as polarization and groupthink.The theories of group decision alert the analyst to ways in which group decisions can be badly made: they may be unfair, unsustainable, arbitrary, or based on poorly shared information, or deliberately or accidentally suppressed dissent. Fortunately, it is possible to design decision processes which make appropriate use of risk and decision analytic technologies, but which are also responsive to the social context in which the decision takes place.