SMS vs email appointment reminders.

A 2011 systematic review of 29 studies found SMS and automated reminders reduce healthcare no-shows by 28 to 38%. Email alone is weaker, around 15 to 20%. Here is the full evidence.

Evidence base

Key studies

Study	N	Setting	Reduction
Hasvold & Wootton 2011 (primary)	29 studies	Hospital outpatient (mixed)	29% SMS / automated, 39% phone
Cochrane review (Gurol-Urganci 2013)	4 RCTs (3,547)	Healthcare (mixed)	RR 1.10 attendance

Citation archive with DOI links →

Timing

Optimal timing

48 hours before

Full reminder with all details

22% reduction alone

2 hours before

Brief confirmation prompt

+12 to 16% additional

No reply by T-4hr

Staff callback + waitlist notify

Mitigates remaining gap

Channel

SMS vs email vs phone

SMS (two-way confirmation)

Highest effectiveness, fastest

28 to 38%

SMS (one-way)

Good baseline

20 to 25%

Additive to SMS, not replacement

15 to 20%

Phone call

Most effective per contact, not scalable

35 to 45%

Patient portal message

Additive for established patients

10 to 15%

TCPA compliance

US healthcare SMS rules

The Telephone Consumer Protection Act (TCPA) requires written consent before sending automated SMS messages to US mobile numbers. For healthcare appointment reminders:

·Obtain express written consent at patient intake (paper or digital form)
·HIPAA-covered entities: appointment reminders are “treatment, payment, operations” communications. Consent is implicit if the patient provided their number.
·Always provide an opt-out mechanism (reply STOP)
·Restaurant and salon reminders require explicit opt-in as they are commercial messages
·Most reminder platforms (Weave, SolutionReach, Fresha) handle TCPA compliance automatically

Reduce hub Overbooking math Policy templates Reminder platforms Research

Margin notes

Do SMS reminders work for reducing no-shows?+

Yes. Hasvold and Wootton's 2011 systematic review of 29 studies found SMS and automated reminders reduce healthcare no-shows by 28 to 38%. This is the strongest evidence base of any single intervention. Two-way confirmation (requiring patient reply) adds approximately 15% effectiveness.

How many reminders should I send?+

The evidence supports two reminders: one 48 hours before the appointment and one 2 hours before. Three or more do not significantly improve outcomes over two and increase opt-out rates. The 48-hour reminder should include full appointment details. The 2-hour reminder should be brief and action-focused.

Is SMS or email better for appointment reminders?+

SMS significantly outperforms email for no-show reduction. SMS open rates are 98% versus 20-30% for email. Hasvold and Wootton 2011 shows SMS and automated reminders achieve 28-38% reduction versus 15-20% for email. However, email adds an additional 8-12% reduction when combined with SMS, making both together optimal.