Table 1.

Correlation matrix of individual items and the patient safety grade

	Patient safety grade (Spearman correlation coefficient)	Reliability (Cronbach's α)
Staffing and resource adequacy (PES-NWI)		0.78
Adequate support services allow me to spend time with my patients	0.27*
Enough time and opportunity to discuss patient care problems with other nurses	0.34*
Enough registered nurses on staff to provide quality patient care	0.43*
Enough staff to get the work done	0.41*
Collegial nurse–physician relations (PES-NWI)		0.89
Physicians and nurses have good working relationships	0.27*
Physicians value nurses’ observations and judgements	0.20*
Physicians recognise nurses’ contributions to patient care	0.20*
A lot of team work between nurses and physicians	0.22*
Physicians respect nurses as professionals	0.24*
Collaboration between nurses and physicians	0.26*
Physicians hold nurses in high esteem	0.23*
Nurse manager ability, leadership and support of nurses (PES-NWI)		0.76
A supervisory staff that is supportive of nurses	0.39*
A nurse manager who is a good manager and leader	0.30*
Praise and recognition for a job well done	0.29*
A nurse manager who backs up the nursing staff in decision making, even if the conflict is with a physician	0.27*
RNs’ level of involvement in direct patient care
How would you describe your role in caring for most of the patients on your most recent shift?	−0.04*
Patient safety culture (HSOPSC)
Staff feel like their mistakes are held against them	−0.32*
Important patient care information is often lost during shift changes	−0.39*
Things ‘fall between the cracks’ when transferring patients from one unit to another	−0.35*
Staff feel free to question the decisions or actions of those in authority	0.27*
In this unit, we discuss ways to prevent errors from happening again	0.36*
We are given feedback about changes put into place based on event reports	0.32*
The actions of hospital management show that patient safety is a top priority	0.44*

Reliability of PES-NWI subscales is included.

*p<0.0001.

HSOPSC, Hospital Survey on Patient Safety Culture; PES-NWI, Practice Environment Scale of the Nursing Work Index; RNs, registered nurses.