Table 4.

Mixed-effects Poisson regression: association between staffing and high acuity 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	0.982	0.972 to 0.992	<0.001	0.982	0.972 to 0.992	<0.001
NA staffing	1	0.990 to 1.01	0.822	1	0.991 to 1.01	0.791
Patient turnover	0.997	0.988 to 1.01	0.59	0.997	0.988 to 1.01	0.582
Observations in higher acuity patients	1.01	0.936 to 1.09	0.769	1.01	0.937 to 1.09	0.747
RN staffing × NA staffing				0.999	0.994 to 1.00	0.64

Model A: AIC 76747; BIC 76796. Model B: AIC 76749; BIC 76806.

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