  Complex problems often require coordinated group effort and can consume
significant resources, yet our understanding of how teams form and succeed has
been limited by a lack of large-scale, quantitative data. We analyze activity
traces and success levels for ~150,000 self-organized, online team projects.
While larger teams tend to be more successful, workload is highly focused
across the team, with only a few members performing most work. We find that
highly successful teams are significantly more focused than average teams of
the same size, that their members have worked on more diverse sets of projects,
and the members of highly successful teams are more likely to be core members
or 'leads' of other teams. The relations between team success and size, focus
and especially team experience cannot be explained by confounding factors such
as team age, external contributions from non-team members, nor by group
mechanisms such as social loafing. Taken together, these features point to
organizational principles that may maximize the success of collaborative
endeavors.
