Expert Decision Making Robert J. B. Hutton, Gary Klein Klein Associates Inc., 1750 Commerce Center Boulevard North, Fairborn, OH 45324 Received Received May 6, 1998; Revised revised August 12, 1998; Accepted accepted January 29, 1999 ABSTRACT The purpose of this paper is to outline the key aspects of how experts make decisions. The central theme of the paper is that decision making in dynamic settings is perceptual rather than conceptual. In high stress, time-pressured, high stakes, or uncertain environments, the decision maker rapidly assesses the situation and implements a workable course of action. This is referred to as a recognitional approach to decision making. This is in contrast to the view that decision makers gather all the available information, conduct exhaustive, concurrent analysis of the available options, and then choose the optimum solution. This analytical approach also suggests that the reasons for nonoptimal decisions are based on human biases and heuristics. These lines of decision-making research have implications for both the design of, and training for, complex systems. The purpose of this paper is to provide an overview of the pertinent literature and to serve as a resource for further exploration into the implications for decision aiding, decision support, and complex system design. © 1999 John Wiley & Sons, Inc. Syst Eng 2: 3245, 1999 1. INTRODUCTION Why is understanding expert decision making of interest? Understanding decision making has implica- tions for both design and training in complex manma- chine systems. Decision supports and decision aids are technologies which rely heavily on understanding how decisions are made in the context of the task, the goal being to try to improve performance through supporting human decision makers. This support can be provided by an understanding of how good decision makers make use of information available to them to assess a situation or define a problem, to help them maintain an ongoing awareness of the situation as it unfolds, and by helping them to implement good solutions to incidents as they arise. Several key aspects of expert decision making are presented in this paper. The main emphasis that is put on expert decision making is on the ability of the expert to maintain an ongoing situation awareness through perceptual and recognitional skills. The second key aspect of expert decision making is that the conse- quence of an accurate assessment and awareness of a situation usually leads to consideration of a single, feasible course of action. This course of action may be evaluated through the use of mental simulation, and, if it is found to be unsatisfactory, an alternate solution is sought. This occurs in a serial fashion as opposed to many alternatives being considered or weighed simul- taneously. This process allows the decision maker to arrive at workable solutions under multiple task con- straints, such as time pressure, high stakes, ill-defined goals, and uncertainty. The view of expert decision making presented here is perceptual rather than conceptual. It is more a matter of how people see the world than the knowledge that Regular Papers © 1999 John Wiley & Sons, Inc. CCC 1098-1241/99/010032-14 32