Table S2.

Pretest discrete choice experiment results (n=200)

Attribute	Levels	Mean utilities	Lower 95% CI	Upper 95% CI	Mean attribute importance scores (CI)
Initial reminder type	Postal mail	−17.64	−24.87	−10.41	53% (51%–55%)
	Phone call (personal or automated)	19.46	14.25	24.66
	Text message	39.06	32.78	45.34
	Email (from provider’s office or EHR)	61.32	56.36	66.28
	Social media (Facebook, Twitter, etc.)	−121.15	−128.38	−113.92
	Electronic calendar (Outlook, Gmail, etc.)	18.95	12.82	25.08
Arrival of initial reminder	1–5 days prior to appointment	19.88	16.13	23.63	16% (14%–17%)
	6–14 days prior to appointment	11.23	8.61	13.84
	15–30 days prior to appointment	−12.56	−15.54	−9.59
	>1 month prior	−18.55	−22.28	−14.81
Reminder content	Clinic location information (clinic address, directions and map)	5.62	1.07	10.17	23% (21%–24%)
	Rescheduling information (phone number or email)	−4.89	−9.71	−0.08
	Reason for visit	−17.09	−21.7	−12.48
	Clinic location information (clinic address, directions and map) and rescheduling information (phone number or email)	13.57	9.14	17.99
	Clinic location information (clinic address, directions and map) and reason for visit	4.44	0.03	8.86
	Rescheduling information (phone number or email) and reason for visit	−5.79	−9.68	−1.9
	Clinic location information (clinic address, directions and map), rescheduling information (phone number or email) and reason for visit	4.15	0.11	8.18
Number of reminders	1 reminder	6.53	3.13	9.93	9% (8%–10%)
	Multiple reminders–same type	−5.9	−8.07	−3.73
	Multiple reminders–different types	−0.63	−3.33	2.06

Abbreviations: CI, confidence interval; EHR, electronic health record.