‘Crowd wisdom’ refers to the surprising accuracy that can be attained by averaging judgments from independent individuals. However, independence is unusual; people often discuss and collaborate in groups. When does group interaction improve vs. degrade judgment accuracy relative to averaging the group's initial, independent answers? Two large laboratory studies explored the effects of 969 face-to-face discussions on the judgment accuracy of 211 teams facing a range of numeric estimation problems from geographic distances to historical dates to stock prices. Although participants nearly always expected discussions to make their answers more accurate, the actual effects of group interaction on judgment accuracy were decidedly mixed. Importantly, a novel, group-level measure of collective confidence calibration robustly predicted when discussion helped or hurt accuracy relative to the group's initial independent estimates. When groups were collectively calibrated prior to discussion, with more accurate members being more confident in their own judgment and less accurate members less confident, subsequent group interactions were likelier to yield increased accuracy. We argue that collective calibration predicts improvement because groups typically listen to their most confident members. When confidence and knowledge are positively associated across group members, the group's most knowledgeable members are more likely to influence the group's answers.

“群众智慧”是指通过平均独立个人的判断可获得的惊人准确性。但是，独立是不寻常的。人们经常在小组中讨论和合作。相对于对小组初始的独立答案取平均，小组互动何时能改善而不是降低判断准确性？两项大型实验室研究探讨了969次面对面讨论对211个团队的判断准确性的影响，这些团队面临着从地理距离到历史日期到股票价格的一系列数值估计问题。尽管参与者几乎总是希望通过讨论使他们的答案更加准确，但是小组互动对判断准确性的实际影响却是确定的。重要的是，一种新颖的，集体级别的集体信度校正方法相对于小组最初的独立估计，有力地预测了讨论何时会影响或损害准确性。当小组在讨论之前进行集体校准时，更准确的成员对自己的判断更有信心，而较不准确的成员则对自己的判断没有信心，则随后的小组互动更可能产生更高的准确性。我们认为，集体校准可预测会有所改善，因为小组通常会倾听他们最自信的成员。当组成员之间的信心和知识成正相关时，组中知识最丰富的成员更有可能影响组的答案。