Unexpected Worker Absences as Labor Supply Shocks: Evidence from Ambulance Services

We estimate the short-run marginal product of ambulance labour in emergency care. Using comprehensive administrative data on hospitals and ambulance stations, we exploit quasi-random variation in staffing shortages generated by unexpected sickness absences across ambulance stations serving the same emergency department. We find that a one-standard-deviation increase in ambulance staff sickness absences raises patient mortality within 24 hours of emergency department arrival by 0.78%. The effects are concentrated among high-risk patients and during periods of peak demand, highlighting the critical role of ambulance labour in the production of emergency care.