Student and team performance in 17 sections of an introductory microeconomic theory course taught using team-based learning are analyzed to determine what measurable characteristics of teams influence team and individual outcomes. Results suggest that team performance is positively influenced by the grade point average of the top individual on the team as well as the percentage of females on the team. While the level of cooperation within a team does not significantly influence team outcomes, it positively influences individual performance by females while having no statistically significant influence on male performance. Individual success also is positively and significantly influenced by gender diversity and individual effort in team activities, as measured by peer evaluations. These results are robust to a variety of measures of gender diversity.