Doctors' response to queues: Evidence from a Portuguese emergency department.

We evaluate how doctors in an emergency department react to the number of patients waiting for treatment. Our outcomes reflect the time spent with the patient, the intensity of treatment, and discharge destination. Using visit-level data in a Lisbon-area hospital, we use a fixed effects model to exploit variation in the queue size while addressing endogeneity using the number of arrivals to the hospital in the previous 60 min as an instrumental variable. Furthermore, we estimate doctors' reactions separately for patients with different degrees of urgency, as measured by the Manchester triage system. Results show that doctors discharge patients more rapidly as queues become longer, and this effect is stronger for patients that do not have life-threatening conditions. We also find that the intensity of diagnosis/treatment procedures decreases when patients face longer queues, driven by the extensive margin. Finally, doctors are less likely to admit patients to inpatient care. We interpret the results in the light of the doctors' incentives literature, explaining how these agents behave in the context of a National Health Service, with no financial incentives.