Each extra patient per nurse increases patient death risk by 16%

Only one US state (California) mandates nurse-to-patient ratios by law. In every other state, hospitals set their own staffing levels, and when census is high or nurses call out sick, remaining nurses absorb extra patients. Research shows each additional patient added to a nurse's assignment increases the odds of a patient dying by 16%. Hospitals staffing at 1:8 ratios experience five additional deaths per 1,000 patients compared to 1:4 ratios. So what? Preventable deaths occur at scale — an estimated 4,370 excess Medicare patient deaths over two years in New York State alone would have been avoided with safe staffing. So what? Surviving patients also experience more falls, pressure ulcers, and hospital-acquired infections, extending stays and increasing costs. Why does this persist? Hospital administrators face a perverse incentive: mandating ratios would require hiring more nurses (expensive) or capping admissions (lost revenue). Lobbying groups have successfully blocked ratio legislation in 49 states for decades.