What the data says about missed appointments
The strongest Canadian figure comes from a study run in four family medicine teaching units at the University of Montreal: of 34,619 scheduled appointments, 2,700 were not kept, or 7.8%, ranging from 6.3% to 9.0% between units [1].
At the other end of the scale, an inner-city clinic in Saskatoon measured 24.6% non-attendance across 1,976 appointments, and 77.8% of the missed appointments had been booked more than a week ahead [2]. A review in the Canadian Medical Association Journal cites an international average of about 23%, with 10% in Quebec and 25% in Saskatchewan [3].
The British health system publishes the same kind of measure at scale: of 146.1 million outpatient appointments in 2024-25, 113.2 million were attended, and non-attendance accounts for 5.6% of the total, down from 5.9% the year before [4].
The three costs of an empty slot
An empty slot costs three times, and the three costs do not show up in the same place:
- the person’s time: they are there, they are paid, and they serve nobody during that block;
- the resource tied up: an exam room, a bay, a device, or a part ordered for a vehicle that will not come;
- the next customer: the slot could not be given to someone who was waiting, and it does not come back.
The British system put an order of magnitude on it at its own scale: a 5% non-attendance rate costs it £216 million a year [3]. That is a health-system figure, not a business one — but it shows that the cost of a percentage of absence is never a percentage.
Redoing the calculation with your numbers
The formula fits on one line: appointments per month × non-attendance rate × average revenue per appointment. The first two factors can be measured in the calendar; the third belongs to the business.
An arithmetic example, and it is given as such — it is not a measured figure: a business that receives 1,000 appointments a month and does not have 7.8% of them kept loses 78 slots a month, at the rate measured in the Quebec study [1]. The amount of the loss then depends on the average revenue per appointment, which only the business knows.
What clinical trials say about reminders
Reminders have been tested seriously, and the results are documented:
- a systematic review and meta-analysis of 21 studies (8,345 notified patients, 7,731 without notification) concludes that notified patients were 23% more likely to attend, with a non-attendance rate of 15% against 21% without notification [5];
- the same review finds that several notifications work better than one [5];
- a Cochrane review of eight randomised controlled trials with 6,615 participants concludes that text message reminders increase attendance compared with no reminder or a postal reminder, with an effect comparable to phone call reminders, and two studies report a cost per attendance lower than phone calls [6].
Those trials are about clinics, not about garages or hair salons. Nothing suggests the effect is weaker there; nothing proves it either. That is a limit worth knowing before promising a figure to a business in another trade.
Why a reminder costs little and an empty slot costs a lot
An automatic reminder is one message per appointment, sent by the system, with nobody having to pick up the phone. An empty slot is a block of someone’s day, a room or a bay left idle, and sometimes a part ordered for nothing.
The asymmetry is structural: the reminder is paid once per appointment, while the empty slot is paid once per absence — and it cannot be recovered, because the hour has passed.
The detail that decides: the customer’s answer
A reminder that offers no way to answer is a notification. A reminder that opens a confirmation page is a conversation: the customer says yes, or says they are not coming.
That detail is not cosmetic. In the Quebec study, lack of confirmation is one of the organisational reasons given by patients who missed an appointment (13.7%), and more than half (55.2%) simply say they forgot to tell the clinic [1]. The reminder does not make the customer come: it makes their answer arrive early enough for the slot to serve someone else.
What a reminder does not fix
Not every absence is a lapse of memory. In the same study, patients also cite feeling better (22.9%), work obligations (19.9%), another medical appointment at the same time (15.7%), transport problems (15.1%) and being too unwell to travel (13.9%) [1]. A message fixes neither transport, nor childcare, nor a work schedule.
- a reminder does not replace a clear cancellation policy, nor a deposit required for some appointments;
- a reminder does not replace an up-to-date waiting list: there still has to be someone to give the freed slot to;
- a reminder does not fix appointment delays that are too long, which are themselves a cause of absence [1].
Three questions to ask before choosing an automatic reminder
- Can the customer answer the message, or only read it? A reminder with no way to answer leaves the slot blocked until the day itself.
- What happens if the customer has neither email nor text consent? The answer has to be stated in advance: the office confirms, or the agent tells the truth on the phone.
- Is the appointment cancelled automatically when the customer does not answer? A system that cancels on silence turns a distracted customer into a lost one.
VoxAgenda answers those three questions the same way everywhere: the reminder goes out two days ahead with a confirmation link, email takes over when a text message is not possible, and no appointment is cancelled automatically. The full path is described on the How it works page.
Sources
Every figure in this article points to one of the sources below. References [1] to [6] follow that order.
Claveau J, Authier M, Rodrigues I, Crevier-Tousignant M. « Patients’ missed appointments in academic family practices in Quebec ». Can Fam Physician 2020;66(5):349-355.
Canadian Family Physician — College of Family Physicians of Canada · May 2020
Of 34,619 scheduled appointments across four family medicine units, 2,700 were not kept, or 7.8% (from 6.3% to 9.0% depending on the unit). Organisational reasons cited: inconvenient time 17.0%, delay before the appointment 14.6%, lack of confirmation 13.7%. The most frequent reason for not telling the clinic was forgetting to call (55.2%).
https://www.cfp.ca/content/66/5/349Shahab I, Meili R. « Examining non-attendance of doctor’s appointments at a community clinic in Saskatoon ». Can Fam Physician 2019;65(6):e264-e268.
Canadian Family Physician — College of Family Physicians of Canada · June 2019
Of 1,976 appointments booked between January and June 2016 at a community clinic in Saskatoon, 487 were not kept, or 24.6%. 77.8% of the missed appointments had been booked more than a week ahead.
https://www.cfp.ca/content/65/6/e264Glauser W. « When patients miss appointments, everyone pays ». CMAJ 2020;192(6):E149-E150. doi:10.1503/cmaj.1095840.
Canadian Medical Association Journal · 10 February 2020
The British National Health Service reported that a 5% non-attendance rate cost it £216 million in one year. The article also reports non-attendance rates of 10% in Quebec and 25% in Saskatchewan, and an international average of about 23%.
https://doi.org/10.1503/cmaj.1095840NHS Digital. « Hospital Outpatient Activity 2024-25 — Summary Report ».
National Health Service England — accredited national statistics · Published 25 September 2025 (data from 1 April 2024 to 31 March 2025)
146.1 million outpatient appointments, of which 113.2 million were attended. “Did not attend” accounts for 5.6% of appointments in 2024-25, against 5.9% in 2023-24 and 6.2% in 2019-20.
https://digital.nhs.uk/data-and-information/publications/statistical/hospital-outpatient-activity/2024-25/summary-reportsRobotham D, Satkunanathan S, Reynolds J, Stahl D, Wykes T. « Using digital notifications to improve attendance in clinic: systematic review and meta-analysis ». BMJ Open 2016;6(10):e012116. doi:10.1136/bmjopen-2016-012116.
BMJ Open · 2016
Systematic review and meta-analysis of 21 studies (8,345 patients with electronic notification, 7,731 without). Notified patients were 23% more likely to attend (relative risk 1.23; 67% against 54%). Non-attendance was 15% with notification against 21% without (relative risk 0.75). Multiple notifications were more effective than a single one.
https://bmjopen.bmj.com/content/6/10/e012116.fullGurol-Urganci I, de Jongh T, Vodopivec-Jamsek V, Atun R, Car J. « Mobile phone messaging reminders for attendance at healthcare appointments ». Cochrane Database of Systematic Reviews 2013, art. CD007458. doi:10.1002/14651858.CD007458.pub3.
Cochrane Collaboration · 5 December 2013
Eight randomised controlled trials, 6,615 participants. Text message reminders increase attendance at healthcare appointments compared with no reminder or a postal reminder, with an effect comparable to telephone reminders; two studies report a lower cost per attendance than phone reminders. The evidence is of low to moderate quality.
https://www.cochrane.org/evidence/CD007458_mobile-phone-messaging-reminders-attendance-healthcare-appointments
- How it works
The call, the appointment, the confirmation and the reminder, step by step.
- Pricing and what is included
What is billed, what is not, and how to get a written quote.
- Frequently asked questions
Fourteen short answers about language, consent, calendar and data.