NIOSHTIC-2 Publications Search

California's nurse-to-patient ratio law and occupational injury.

Leigh JP; Markis CA; Iosif AM; Romano PS
Int Arch Occup Environ Health 2015 May; 88(4):477-484
OBJECTIVE: To determine whether state-mandated minimum nurse-to-patient staffing ratios in California hospitals had an effect on reported occupational injury and illness rates. METHODS: The difference-in-differences method was applied: The change in injury rates among hospital nurses after implementation of the law in California was compared to the change in 49 other states and the District of Columbia combined. Data were drawn from the US Bureau of Labor Statistics and the California Employment Development Department, including numerator estimates of injury and illness cases and denominator estimates of the number of registered nurses (RNs) and licensed practical nurses (LPNs) employed in hospitals. Confidence intervals (CIs) for rates were constructed based on assumptions that favored the null hypothesis. Results: The most probable difference-in-differences estimate indicated that the California law was associated with 55.57 fewer occupational injuries and illnesses per 10,000 RNs per year, a value 31.6 % lower than the expected rate without the law. The most probable reduction for LPNs was 38.2 %. Analyses of CIs suggested that these reductions were unlikely to be due to chance. Conclusions: Despite significant data restrictions and corresponding methodological limitations, the evidence suggests that the law was effective in reducing occupational injury and illness rates for both RNs and LPNs. Whether these 31.6 and 38.2 % reductions are maintained over time remains to be seen. <a href=""target="_blank">An Erratum correcting the error in the abstract and Table 2 has been published.</a> The changes to the abstract have been incorporated into the text above.
Health-care-personnel; Health-care; Health-care-facilities; Nurses; Nursing; Quality-standards; Health-standards; Regulations; Work-practices; Work-performance; Injuries; Injury-prevention; Statistical-analysis; Mathematical-models; Author Keywords: Legislation; Job-related injury; Illness; Ratios
J.P.Leigh, Center for Healthcare Policy and Research, University of California, Davis, School of Medicine, Sacramento, CA, USA
Publication Date
Document Type
Journal Article
Email Address
Funding Type
Cooperative Agreement; Agriculture
Fiscal Year
Identifying No.
Cooperative-Agreement-Number-U54-OH-007550; M092014
Issue of Publication
Priority Area
Agriculture, Forestry and Fishing
Source Name
International Archives of Occupational and Environmental Health
Performing Organization
University of California - Davis
Page last reviewed: May 11, 2023
Content source: National Institute for Occupational Safety and Health Education and Information Division