“…Thus, similar to previous studies, [14][15][16] we categorized nursing homes into quartiles to capture such nonlinear associations: nursing homes with low proportions of racial/ethnic minority residents (<2.92%, the 25th percentile), medium proportions (2.92%-11.11%, the median), medium-high proportions (11.11%-30.18%), and high proportions (≥30.18%, the 75th percentile). From the NHC files, we obtained a set of nursing home covariates that were found important to COVID-19 infections or deaths, [16][17][18][19] including number of beds, average daily resident census, ownership status (for profit, nonprofit, or government owned), chain affiliation (yes/no), whether the nursing home is affiliated with a hospital, percentage of Medicare residents, percentage of Medicaid residents, average staffing levels (hours per resident day) for RN and for all nursing staff (including RNs, LPNs/LVNs, and certified nursing assistants) in 2019, and five-star ratings for overall quality of care. RN and other nurse staffing levels were calculated based on daily resident census and CMS Payroll-Based Journal system through which nursing homes electronically submit the number of hours that agency and contract staff are paid to work each day; the payroll-based data are submitted quarterly and audited by CMS to ensure accuracy.…”