Communication and shared mental models are key elements to effective teamwork. This study explored whether simulation-based closed-loop communication training would improve staff perceptions of communication ability and decrease medical errors. Increases in perception of closed-loop communication ability were sustained one-month after training. A retrospective chart review of all emergency severity index (ESI) level 1 patients (n=9) seen in the 4-months pre- and post-training showed a reduction in medical errors (89% to 56%, respectively).