It is common lore in North American teaching hospitals that, come 24 June, everyone needs to pay close attention to what the new house officers (interns) are doing. Nurses, staff physicians and pharmacists all band together to make sure that these fledgling doctors do no harm in their first days and weeks. I still recall my first night on call, and how the ward nurses all gently “suggested” solutions to the patient care issues they were contacting me about.

This careful oversight of others’ behaviour is crucial for patient safety. James Reason’s “Swiss cheese model” of accident causation illustrates one paradigm for understanding how errors occur in complex systems.1 The nurses’ vigilance when new interns begin represents one of the crucial safeguards against error he describes. The direct interaction between order provider and receiver during a verbal order allows the receiver to provide feedback and input into patient care in a way that they cannot with a written or computer-generated request. The Joint Commission requires that patient handoffs include …