. Author manuscript; available in PMC: 2011 Sep 1.

Published in final edited form as: Res Nurs Health. 2010 Oct;33(5):413–425. doi: 10.1002/nur.20399

Table 3.

Incident Rate Ratios of Patient Falls Based on Negative Binomial Regressions

	Model 1, IRR (n = 50,810)	Model 2, IRR (n = 50,810)	Model 3 (ICU), IRR (n = 11,520)	Model 4 (non-ICU), IRR (n = 39,290)
Nurse staffing
RN Hppd	0.910^***	0.984^***	0.967^***	0.994
LPN Hppd	1.015	1.030^**	1.098^**	1.035^**
NA Hppd	1.043^***	1.011^*	0.989	1.015^*
Magnet hospital	0.948^***	0.947^***	0.860^***	0.960^**
Nursing unit type			N/A
ICU		0.211^***
Stepdown		0.484^***		0.471^***
Medical		0.632^***		0.627^***
Surgical		0.397^***		0.396^***
Med-surg		0.545^***		0.544^***
Rehab		Reference		Reference
R²	0.030	0.049	0.008	0.019

Notes:

^***

p < .001,

^**

p < .01,

p < .05.

Observations are nursing unit months.

Incident rate ratios are from generalized estimating equations models that clustered observations within nursing units.

Models 2, 3, and 4 controlled for the hospital’s 2004 Medicare Case Mix Index, teaching status, bedsize, and ownership, and the nursing unit’s average patient age and sex.

RN, registered nurse; LPN, licensed practical nurse; NA, nursing assistant; Hppd, hours per patient day; ICU, intensive care unit; Med-Surg, medical-surgical; Rehab, rehabilitation.