How do collective incentives contribute to team effectiveness? With a field study (71 interviews) and the IMO (Inputs - Mediators - Outcomes) model, we found that major inputs of team effectiveness are: the staff performance management process (SMART objectives, reliable performance appraisals, hybrid incentives), manager’s abilities to ensure equity, task interdependence, and a few team members’ characteristics (job level, perf ormance level, culture ). Major positive and negative mediators are: F ree - riding, team spirit, mutual aid, work commitment and mutual motivation . Our findings indicate that collective incentives are one of the several major inputs of team effectiveness. They also reveal that team spirit is perhaps an important component of team cohesion or a new higher - level construct which should be further inves tigated.