Do reminders reduce no-shows? What the research says

The short answer

Yes, in the places researchers have tested them. A 2016 review pooled 21 randomized clinic studies and found that patients sent text reminders were 25% less likely to miss their appointment. Experiments with flu shots, court dates, elections and gym visits mostly found gains as well, by amounts that swing widely from one study to the next. The reminders came as texts, letters, emails and phone calls, and none of these studies put an event in someone's calendar app.

What did the 2016 review of clinic reminders find?

Dan Robotham and colleagues at King's College London pooled studies of text-based reminders for healthcare appointments and published the results in BMJ Open in 2016. Their main analysis took 21 randomized studies that compared patients who got reminders with patients who got none. Every one of those 21 sent SMS text messages, and one paired them with phone calls and letters.

Patients who received notifications were “23% more likely to attend clinic,” in the authors' words, with 67% attending against 54%. They were also “25% less likely to ‘no show’” for appointments: 15% missed, against 21% of patients with no reminder. The review found multiple notifications “significantly more effective at improving attendance than single notifications,” and voice reminders “appeared more effective” than text. The studies ran in Europe (nine), Asia (seven), Africa (two), Australia (two) and America (one).

Have reminders been tested outside clinics?

They have. Each study below measured a different outcome with different people, so their numbers can't be lined up against each other.

Study	Setting	What people got	What it found
Milkman and colleagues, 2011, PNAS	Free flu shot clinics a large firm held for its employees	A mailed reminder listing clinic times and places. Some letters also asked people to write down the date, or the date and time, they planned to go	With the date and time prompt, vaccination ran 4.2 percentage points above the 33.1% rate for the plain reminder, a statistically significant gap. The date-only prompt added 1.5 points, which the authors found not statistically significant
Milkman and colleagues, 2021, PNAS	47,306 patients at Penn Medicine and Geisinger with a primary care visit coming up, in fall 2020	Texts from one of 19 programs in the three days before the visit, or none	The 19 programs raised vaccination by an average of 2.1 percentage points, or 5%. The best one reminded patients twice and said a flu shot was reserved for them
Fishbane, Ouss and Shah, 2020, Science	People summoned to court in New York City for low-level offenses	A series of texts in the week before the court date with details such as the time and place, for people who had given a phone number	Failures to appear fell 21%. A redesigned summons form, tested separately, cut them by 13%
Dale and Strauss, 2009, American Journal of Political Science	A nationwide experiment with 8,053 people in the 2006 US election	Text message reminders to vote	A “statistically significant 3.0 percentage point increase in the likelihood of voting”
Nickerson, 2008, Quarterly Journal of Political Science	13 field experiments with 232,716 people	Email campaigns for voter registration and turnout	“Both registration and turnout were unaffected”
Malhotra, Michelson and Valenzuela, 2012, Quarterly Journal of Political Science	Registered voters in San Mateo County, California, over three rounds	Unsolicited emails from the county registrar, or the same message from a fictional voter mobilization group	The registrar's emails raised turnout by amounts the authors call “small, but statistically significant.” The fictional group's emails had no measurable effect
Habla and Muller, 2021, Experimental Economics	Almost 2,500 members of a large health club in Sweden who had recently bought an annual membership	Weekly email reminders for three months, sent to half of them	Weekly visits rose 13%, by 19% for classes and 11% for free training. The rise held through the three months after the emails stopped

Why would a reminder change what people do?

Habla and Muller put the gym result down to attention and habit: “limited attention and habit formation can best explain these results,” they write. For the court study, Chicago Booth's release says the findings “suggest many defendants’ failure to appear (FTAs) are the result of human error.” Todd Rogers and three co-authors reviewed the research on planning prompts in 2015. Such prompts “seem to work because scheduling tasks makes people more likely to carry them out,” in their account, and they help people recall a task “in the right moment.”

Two of the studies favor sending more than one reminder. Robotham's review found multiple notifications did more for attendance than a single one, and the top program in the 2021 flu study reminded patients twice.

Did any of these studies test calendar apps?

None of them did. Every reminder here arrived as a text, a letter, an email or a phone call, and no study compared a calendar alert with any of those, so the research can't say whether an event in someone's calendar cuts no-shows by more than a text does or by less.

How can you find out for your own events?

Run the kind of test the researchers ran. Split your list at random and send reminders to one half only, then compare how many from each half turn up. Turnout is the number to count, from check-ins, scanned tickets, kept bookings or the list at the door. Email opens make a poor stand-in, since Apple Mail can report an email as opened when nobody read it, as our guide to Apple Mail Privacy Protection and open rates explains.

To test a calendar, put your events in the calendars of a random half of your followers and compare their turnout with the rest. Our comparison of reminders by calendar, email, text and app push goes through what each channel asks of customers.

Where TheyCal fits

We make TheyCal, which puts a business's events in its followers' own calendars. The business picks each event's alert, anywhere from 10 minutes to a week ahead, and can add a second one. We haven't published data on whether this cuts no-shows, so a business that wants to know can run the split test above and compare turnout.

Common questions

How much do text reminders reduce no-shows?

Across the 21 clinic studies in Robotham's review, 15% of patients sent reminders missed their appointment, against 21% of those sent none. In New York City, text reminders cut failures to appear in court by 21%.

Is one reminder enough?

The clinic review found multiple notifications “significantly more effective at improving attendance than single notifications.” In the 2021 flu study, the top program sent two texts.

Do email reminders work?

Weekly emails raised gym visits 13% in Habla and Muller's study. Across 13 experiments, Nickerson found that email left voter registration and turnout where they were. When the email came from the county registrar, Malhotra's team saw turnout rise by a small amount, and the same message from a fictional group had no measurable effect.

Do calendar reminders reduce no-shows?

We didn't find a published study that tested them. The research above covers texts, letters, emails and calls.