When it comes to athletics sports teams have a specific number of team players: A basketball team needs five baseball nine and soccer 11. But when it comes to the workplace there is no hard-and-fast rule to determine the optimal number to have on each team. Should the most productive team have 4.6 members as suggested in a recent magazine article? What about naming five or six individuals to each team which is the number of MBA students chosen each year by Wharton for its learning teams? Is it true that larger teams simply break down reflecting a tendency towards ”social loafing” and loss of coordination? Or is it that the best number of people for a team is driven by the task at hand and by the roles each person plays? Research by Wharton faculty offers some insights.