In a sample of 1,891 teams (8,556 students) who completed an eight-week international business consulting project, half of the teams developed a team charter, half did not. Teams with charters saw improved process performance metrics only at the forming stage of team development. They also reported higher conflict levels. However, more conflict did not negatively affect peer evaluations or team output quality, suggesting that such conflict was not entirely negative. Team charter use was not directly associated with output quality, measured as the final report's grade.However, team national diversity moderated the solution creativity presented in the team's final report. These findings suggest team charters may initially aid process improvement but not necessarily the quality of output. We propose that the difference between the two groups studied is essentially one of formal written contracting versus informal psychological contracting, defined as a set of unwritten expectations of team members with regard to team behaviors and goals. These two forms of contracting provide for equifinality (the same result) in performance over the lifecycle of a project. The study contributes to research on team charter use, particularly with respect to formal versus informal psychological contracting within the context of global virtual teams.