Table 3.

Mixed-effects Poisson regression: association between staffing and all missed observations with (A) and without (B) inclusion of a linear interaction term between RN and NA staffing levels

Model	A			B
	IRR	95% CI	P value	IRR	95% CI	P value
RN staffing	0.983	0.979 to 0.987	<0.001	0.981	0.977 to 0.985	<0.001
NA staffing	0.954	0.949 to 0.958	<0.001	0.957	0.952 to 0.961	<0.001
Patient turnover	1.01	1.01 to 1.01	<0.001	1.01	1.01 to 1.02	<0.001
Observations in higher acuity patients	4.83	4.68 to 4.99	<0.001	4.8	4.65 to 4.96	<0.001
RN staffing × NA staffing				1.01	1.01 to 1.01	<0.001

Model A: AIC 215974; BIC 216033. Model B: AIC 216062; BIC 216112.

AIC, Akaike information criterion; BIC, Bayesian information criterion; IRR, incidence rate ratio; NA, nursing assistant; RN, registered nurse.