Diagnostic accuracy was not affected by interruptions or time pressure but was related to experience level: Emergency physicians were more accurate (71%) than residents (43%) (F = 234.0, P<.0001) and responded more quickly (54 seconds) than residents (65 seconds) (F = 9.0, P<.005). Response time was shorter for participants in the fast condition (55 seconds) than in the slow condition (73 seconds) (F = 22.2, P<.0001). Interruptions added about 8 seconds to response time.