Table 2. Unadjusted Results and Interrupted Time Series Analysis.

Setting	Mean (SD)			IRR (95% CI)
	Orders, No.	Duplicate Orders, No.	Proportion Duplicate Orders	Level Changea	Change in Trendb	Preintervention Trendc
Laboratory
Before intervention	6.10 (6.13)	0.08 (0.63)	0.01 (0.05)	0.51a (0.45-0.59)	1.00 (1.00-1.00)	1.00 (1.00-1.00)
After intervention	6.21 (5.95)	0.05 (0.48)	0.01 (0.04)
P value	.001	<.001	<.001	<.001	<.001	<.001
Medication
Before intervention	2.81 (3.69)	0.00 (0.07)	0.00 (0.01)	1.17 (0.52-2.61)	1.00 (1.00-1.00)	1.00 (1.00-1.00)
After intervention	3.12 (4.03)	0.01 (0.08)	0.00 (0.01)
P value	<.001	.002	.02	.71	<.001	.08
Radiology
Before intervention	1.12 (1.43)	0.02 (0.15)	0.01 (0.05)	0.61 (0.46-0.82)	1.00 (1.00-1.00)	1.00 (1.00-1.00)
After intervention	1.18 (1.48)	0.01 (0.13)	0.01 (0.05)
P value	<.001	.02	.002	.001	<.001	.007

Abbreviation: IRR, incidence rate ratio.

^aEstimates the immediate change in the incidence of duplicate orders after implementation.

^bEstimates the gradual change in the incidence of duplicate orders over time after implementation.

^cEstimates the preintervention trend in incidence over time.