Theoretical models of groups suggest that sub-group usage can affect communication among members and group decision-making. To examine the trade-offs from forming sub-groups, we assemble a detailed dataset on corporate boards (groups) and committees (sub-groups). Boards have increasingly used committees formally staffed entirely by outside directors. Our data show that twenty-five percent of all director meetings occurred in such committees in 1996; this increased to 45% by 2010. Our evidence suggests that granting formal authority to such committees can impair communication and decision-making. Sub-groups are relatively understudied, but our results suggest that they play an important role in group functioning and corporate governance.

群体的理论模型表明，子群体的使用会影响成员之间的交流和群体决策。为了检查形成子组的权衡，我们收集了关于公司董事会（组）和委员会（子组）的详细数据集。董事会越来越多地使用完全由外部董事组成的正式委员会。我们的数据显示，1996 年所有董事会议中有 25% 是在此类委员会中召开的；到 2010 年，这一比例增加到 45%。我们的证据表明，向此类委员会授予正式权力可能会影响沟通和决策。子集团的研究相对较少，但我们的研究结果表明，它们在集团运作和公司治理中发挥着重要作用。