A procedure whereby one person in a group is assigned the task of trying to find everything that might be wrong in a forecast (or a plan), while the rest of the group defends it. This should be done as a structured approach, perhaps with this role rotating among group members. (Someone adopting this role without permission from the group can become unpopular.) Use the devil’s advocate procedure only for short time periods, say 20 minutes or less if done in a meeting. Cosier’s (1978) experiment showed that groups that used the devil’s advocate procedure obtained more accurate predictions than those who solely argued in favor of a forecast. One would also expect the devil’s advocate procedure to improve the calibration of prediction intervals. According to Cosier (1978) and Schwenk and Cosier (1980), the “attack” is best presented in written form and in an objective manner; the use of strong emotionally laden criticism should be avoided. This research is consistent with findings that peer review leads to improvements in research papers.