OBJECTIVES: The objective was to evaluate whether a standardized consultation model in the emergency department (ED), the 5 Cs of Consultation (Contact, Communicate, Core Question, Collaboration, and Closing the Loop), would improve physicians' ability to relay appropriate information and communicate successfully during a consultation. METHODS: This was a prospective, randomized study at a large, academic, urban, tertiary care medical center in Chicago. Forty-three emergency medicine (EM) and EM/internal medicine (EM/IM) residents were randomized into two groups, an intervention group and an unstructured group, stratified by postgraduate year (PGY). Intervention group participants received an interactive educational session on the 5 Cs of Consultation, a standardized consultation model. Intervention and unstructured groups placed two simulated consultation phone calls, based on pretested simulated patient cases, to a standardized consultant. Three raters, naive to the consultation model and blinded to group assignments, individually assessed recordings of each call using a seven-item, five-point global rating scale (GRS). Finally, an attending surgeon and an attending psychiatrist each rated respective cases using a single global rating to provide validity evidence for the scale. RESULTS: Residents trained with the 5 Cs model communicated significantly better, regardless of PGY and clinical case. The intervention group had significantly higher mean GRS scores than the unstructured group (4.1 vs. 3.5, F(1,39) = 33.5, p < 0.0001). Secondary analysis of the recordings suggested that encounters with more 5 Cs behaviors tended to receive higher GRS scores. CONCLUSIONS: A standardized educational model increased the effectiveness of consultation communication from the ED. Residents trained with the 5 Cs of Consultation scored better on consultation assessments compared with untrained residents. Training programs should consider adopting standardized consultation models.