IMPORTANCE Turnover in health care staff may disrupt patient care and create operational and organizational challenges, and nursing home staff turnover rates are particularly high. Empirical evidence on the association between turnover and quality of care is limited and has typically relied on low-quality measures of turnover, small and selected samples of facilities, and comparisons across facilities that are highly susceptible to residual confounding. OBJECTIVE To quantify the association between nursing home staff turnover and quality of care using within-facility variation over time in reliable turnover measures available for virtually all US nursing homes. DESIGN, SETTING, AND PARTICIPANTS In this cross-sectional study, data from the Centers for Medicare & Medicaid Services on health inspection citations and quality measures at US nursing homes were combined with turnover measures constructed from daily staffing payroll data for quarter 2 of 2017 (April 1 to June 30) to quarter 4 of 2019 (October 1 to December 31), covering 1.06 billion shifts for 7.48 million employment relationships at 15 869 facilities. A 2-way fixed-effects design was used to estimate the association between staff turnover (direct care nursing staff and administrators) and quality-of-care outcomes based on how the same facility performed differently in times of low and high turnover. Data analysis was performed from September 2022 to August 2023. EXPOSURES Facility turnover, defined as the share of hours worked in a period by staff hired within the last 90 days. MAIN OUTCOMES AND MEASURES Number, type, scope, and severity of health inspection citations, overall health inspection scores, and Nursing Home Compare quality measures. RESULTS The study sample included 1.45 million facility-weeks between April 1, 2017, and December 31, 2019, corresponding to 13 826 unique facilities. During an average facility-week, 15.0% of nursing staff and 11.6% of administrators were new hires due to recent turnover. After both administrator turnover and the overall staffing level were controlled for, an additional 10 percentage points in nursing staff turnover in the 2 weeks before a health inspection was associated with an additional 0.241 (95% CI, 0.084-0.399) citations in that inspection, compared with a mean of 5.98 citations. An additional 10 percentage points in nursing staff turnover was associated with a mean decrease of 0.035 (95% CI, 0.023-0.047) SDs in assessment-based quality measures and 0.020 (95% CI, 0.001-0.038) SDs in claims-based quality measures, with the strongest associations found for measures related to patient functioning. CONCLUSIONS AND RELEVANCE Within-facility variation in staff turnover was associated with decreased quality of care. These findings suggest that efforts to monitor and reduce staff turnover may be able to improve patient outcomes.
