EXHIBIT 4.

Relationship Between Nurses’ Shift Length And Outcomes For Patients

	Adjusted coefficients for percent of nurses working in the shift length category
Patient outcome	>13 hours	12–13 hours	10–11 hours	8–9 hours
Patients rated hospital ≤6 of 10a	1.2**	0.1	−1.2	−0.1
Patients would not recommend the hospitalb	0.8**	0.1**	−1.2**	−0.2**
PATIENT OUTCOMES REPORTED AS “SOMETIMES” OR “NEVER”
Nurses communicated wellc	1.0***	0.2***	−1.4***	−0.2***
Staff explained medicationsd	1.1**	0.2**	−1.1	−0.2**
Pain was controllede	0.9***	0.2	−0.9**	−0.1
Patients received help as soon as they wantedf	2.1***	0.3**	−1.3	−0.3***
Room was cleang	0.8	0.3***	−1.7***	−0.4
Staff gave patients discharge informationh	0.5**	0.3***	−2.0***	−0.3***
Doctors communicated welli	0.3	0.2***	−0.9***	−0.2***
Quiet at nightj	0.6	−0.2	−1.1	0.2

SOURCE Authors’ analysis of Multi-State Nursing Care and Patient Safety Study (Note 17 in text), 2005–08, and Hospital Consumer Assessment of Healthcare Providers and Systems survey (Note 15 in text), 2006–07.

NOTES N = 396 hospitals. Adjusted models include nurse age, nurse staffing (see the text), and professional practice environment (see the text); and hospital state, teaching status, ownership, core-based statistical area (a measure of population density), and number of beds. Coefficients are scaled by 10 percent.

^aMean 13; standard deviation 6; range 36.

^bMean 8; standard deviation 4; range 25.

^cMean 8; standard deviation 4; range 20

^dMean 27; standard deviation 6; range 35.

^eMean 9; standard deviation 4; range 22.

^fMean 17; standard deviation 6; range 35.

^gMean 13; standard deviation 4; range 24.

^hMean 24; standard deviation 5; range 28.

ⁱMean 6; standard deviation 2; range 14.

^jMean 20; standard deviation 6; range 35.

^**p < 0.05

^***p < 0.01