Table 2.

Summary of duration, clicks, and accuracy

EHR functions	Usability and safety metrics	Site 1A Mean (SD)	Site 2A Mean (SD)	Site 3B Mean (SD)	Site 4B Mean (SD)
X-ray (left elbow, wrist, forearm)	Task duration (sec)	64.1 (22.4)	24.3 (8.5)	33.3 (9.9)	55.5 (13.3)
	Clicks	31.1 (12.6)	7.7 (3.8)	8.1 (4.9)	15.5 (6.6)
	Error rate Types of errors: - Wrong-site x-ray ordered - Omission of one part of the order (eg, forearm)	25%	16.7%	35.7%	20%
MRI (cervical, thoracic, lumbar)	Task duration (sec)	78.9 (33.4)	66 (25.6)	32.2 (16.1)	79.5 (34.3)
	Clicks	28.9 (13.7)	22.4 (10.5)	14.2 (18.2)	33.3 (15.7)
	Error rate Types of errors: - Omission of one part of the order (eg cervical)	0	8.3%	7.1%	10%
Troponin	Task duration (sec)	5.3 (10.3)	14.2 (24.5)	1.5 (.9)	12.1 (19.7)
	Clicks	2.7 (2.9)	4.3 (9.4)	.9 (.9)	8.2 (16.3)
	Error rate Types of errors: None	0	0	0	0
Lactate (timed order)	Task duration (sec)	20.4 (8)	26.9 (7.9)	12.1 (4.9)	17.5 (15.1)
	Clicks	9.9 (3)	11.1 (3.4)	6 (2.5)	6.6 (5.5)
	Error rate Types of errors: - Ordered for wrong time - Ordered unnecessary tests	0	0	14.3%	0
Tylenol (500 mg PO, 4-6 hours)	Task duration (sec)	51.4 (15.3)	70.4 (32)	69.3 (38.2)	45.6 (15.9)
	Clicks	14 (4.1)	23.5 (15.8)	61.6 (94)	25.8 (11.2)
	Error rate Types of errors: - Wrong dose, frequency, route, and rate	8.3%	0	7.1%	30%
Prednisone taper (60 mg, reduce by 10 mg every 2 days for 12 days)	Task duration (sec)	148.6 (76.1)	152.7 (163.4)	175.1 (73)	178.7 (62.6)
	Clicks	32.2 (16.6)	20 (32.8)	42.3 (17.6)	28.2 (5.7)
	Error rate Types of errors: - Wrong dose	16.7%	41.7%	50%	40%