Teaching residents the two-challenge rule: a simulation-based approach to improve education and patient safety. 
Residents train in a historically hierarchical system.  They may be compelled to question their teachers if they do not understand or disagree with a clinical decision, have a patient safety concern, or when treatment plans are unclear.  We sought to determine whether a debriefing intervention that emphasizes (1) joint responsibility for safety and (2) the "two-challenge rule" (a rubric for challenging others) using a conversational technique that is assertive and collaborative (advocacy-inquiry) can improve the frequency and effectiveness with which residents "speak up" to superiors.  In a simulated operating room, anesthesiology trainees were presented with opportunities to challenge coworkers (eg, orders to administer a relatively contraindicated medication).  Opportunities to challenge the attending faculty anesthesiologist, attending faculty surgeon, and nurse (all confederates) were presented.  When debriefed, subjects were taught the two-challenge rule and a communication technique that paired advocacy (stating trainee's observation) and inquiry (request for the other's reasoning).  A second scenario offered new opportunities to challenge.  Video recorded scenarios were evaluated by two investigators and trainee use of the prescribed advocacy-inquiry language was rated on a 5-point scale.  Forty subjects participated.  Overall use of the two-challenge rule and advocacy-inquiry increased after debriefing.  The debriefing and instruction specifically improved the frequency and quality of challenges directed toward superordinate physicians, without improving resident challenges toward nurses.  This instructional intervention improves "speaking up" by residents to other physicians during simulated obstetric cases.  Providing increased opportunities for resident learning, sharing responsibility for patient safety, and overcoming communication barriers within the medical hierarchy may improve teamwork and patient safety.