The unintended consequences of hospital strikes on patient outcomes evidence from multiple strikes in the Portuguese National Health Service.

Hospital strikes in the Portuguese National Health Service (NHS) are becoming increasingly frequent. This paper analyses the effect of different health professionals' strikes (physicians, nurses, and diagnostic and therapeutic technicians (DTT) - DTT) on patient outcomes and hospital activity. Patient-level data, comprising all NHS hospital admissions in mainland Portugal from 2012 to 2018, is used together with a comprehensive strike dataset with almost 130 protests. Data suggests that hospital operations are partially disrupted during strikes, with sharp reductions in surgical admissions (up to 54%) and a decline on both inpatient and outpatient care admissions. The model controls for hospital characteristics, time and regional fixed effects, and case-mix changes. Results suggest a modest increase in hospital mortality limited for patients admitted during physicians' strikes, and a slight reduction in mortality for patients already at the hospital when a strike takes place. Increases in readmission rates and length of stay are also found. Results suggest that hospitals and legal minimum staffing levels defined during strikes are not flexible enough to accommodate sudden disruptions in staffing, regardless of hospital quality in periods without strikes.