When expert advice works, and when it does not

Both experts and users of expertise fail to grasp the role of expertise in decision making. Of course, expert advice is essential in complex human activities, but those who follow that advice also sometimes regret it. Under what conditions does expert advice and action tend to produce satisfactory outcomes? Recent studies of technological controversies and governmental regulatory procedures reveal some of the conditions under which expert advice may work well, and conditions under which it does not. Before considering these situations, the authors review two mental models (simple and cynical) that obstruct clear thinking about what users of expertise should expect from professional knowledge and what professionals should seek to contribute to technological controversies and other situations requiring expertise