Leaders are important for the smooth functioning of teams but their effect on team performance is less well established. Based on a sample of 55 software development teams from two companies we examined the association between technical leaders' communication structure and the team's performance. Consistent with past research, we found that a team's productivity and quality improve when the team communication follows hierarchical and smallworld patterns, respectively. However, there was significant additional improvement in both productivity and quality when technical leaders shared more information than they gathered, and when they were more central in the communication network. Surprisingly they were not necessarily the most "central" individuals in the team's communication structure. We discuss the implication of these results for new tools that provide feedback to leaders and the team. Copyright © 2014 ACM.