Table 3 Variance and intraclass correlation coefficients (ICCs) at individual, unit and hospital level, corrected for occupation type, years of work at unit and hours a week of work at the unit

Dimension	Individual level	Unit level		Hospital level
Dimension	Variance (SE)	Variance (SE)	ICC (%)	Variance (SE)	ICC (%)
Feedback about and learning from error	0.290 (0.010)*	0.050 (0.011)*	13.8	0.023 (0.013)*	6.2
Overall perceptions of safety	0.297 (0.010)*	0.049 (0.011)*	14.0	0.007 (0.007)	1.9
Teamwork across hospital units	0.304 (0.010)*	0.015 (0.005)*	4.4	0.015 (0.007)*	4.4
Frequency of event reporting	0.665 (0.023)*	0.112 (0.025)*	14.0	0.021 (0.019)	2.6
Supervisor/manager expectations and actions	0.294 (0.010)*	0.030 (0.007)*	9.3	–	–
Teamwork within units	0.205 (0.007)*	0.022 (0.005)*	9.5	0.002 (0.003)	1.0
Non-punitive response to error	0.347 (0.012)*	0.018 (0.006)*	4.7	0.017 (0.009)*	4.5
Smooth transitions	0.392 (0.013)*	0.039 (0.009)*	9.1	–	–
Openness of communication	0.314 (0.011)*	0.014 (0.005)*	4.3	0.004 (0.004)	1.1
Adequate staffing	0.303 (0.010)*	0.144 (0.027)*	31.7	0.007 (0.014)	1.4
Hospital management support	0.408 (0.014)*	0.027 (0.008)*	6.2	0.007 (0.006)	1.6

There was not enough information to obtain estimates at hospital level for Supervisor/manager expectations & actions and Smooth transitions.
*p<0.05.