AbstractThe study of judgment and decision making entails three interrelated forms of research: (1) normative analysis, identifying the best courses of action, given decision makers' values; (2) descriptive studies, examining actual behavior in terms comparable to the normative analyses; and (3) prescriptive interventions, helping individuals to make better choices, bridging the gap between the normative ideal and the descriptive reality. The research is grounded in analytical foundations shared by economics, psychology, philosophy, and management science. Those foundations provide a framework for accommodating affective and social factors that shape and complement the cognitive processes of decision making. The decision sciences have grown through applications requiring collaboration with subject matter experts, familiar with the substance of the choices and the opportunities for interventions. Over the past half century, the field has shifted its emphasis from predicting choices, which can be successful without theoretical insight, to understanding the processes shaping them. Those processes are often revealed through biases that suggest non‐normative processes. The practical importance of these biases depends on the sensitivity of specific decisions and the support that individuals have in making them. As a result, the field offers no simple summary of individuals' competence as decision makers, but a suite of theories and methods suited to capturing these sensitivities. Copyright © 2010 John Wiley & Sons, Ltd.This article is categorized under: Psychology > Reasoning and Decision Making