Table 3.

Summary of the opportunities for an error occurring and high-risk errors that occurred in the three hospitals

Site	Pre-CPOE				Post-CPOE					P value
	Patient records	NOpp	NErr	Error rate (%)	Patient records	NOpp	NErr	Error rate (%)	Relative risk (95% CI)
1	365	3867	167	4.3	297	2634	74	2.8	0.65 (0.49 to 0.86)	0.002
2	615	4513	179	4.0	581	4527	200	4.4	1.11 (0.91 to 1.36)	0.294
3	264	2932	216	7.4	300	2665	116	4.4	0.59 (0.47 to 0.74)	<0.001
Total	1244	11 312	562	5.0	1178	9826	390	4.0	0.80 (0.70 to 0.91)	<0.001

N_Opp represents the number of error opportunities generated, while N_Err is the number of errors that were found to have occurred. P values are from Fisher’s exact tests, with bold values significant at P<0.05.

CPOE, computerised physician order entry.