Definition
No-show rate is the percentage of booked appointments where the customer or patient neither attends nor cancels in time. It is the number of no-shows divided by the number of appointments that were scheduled to take place.
How no-show rate is calculated
The formula is no-shows divided by scheduled appointments, times 100. If a clinic had 200 appointments on the books for a month and 18 people did not arrive and did not cancel, the no-show rate is 18 divided by 200, or 9 percent.
The hard part is the denominator and the definition of a no-show. Teams differ on three points, so write them down before comparing numbers:
- Whether a cancellation made a few hours before counts as a no-show. Many practices set a cutoff, such as 24 hours, and treat anything later as a late cancellation or a no-show.
- Whether appointments the business itself cancelled or moved are in the denominator.
- Whether a person who arrives so late that the visit cannot happen counts.
A rate also hides cost. Missed slots cost more when the appointment is long or the provider cannot be rebooked, so some teams weigh by slot length or revenue, or report lost hours alongside the percentage.
No single industry benchmark is safe to quote, because the definitions above change the result. Compare a practice against its own past months, split by appointment type and booking lead time.
Why it matters for voice agents
Two things in a voice deployment can move this number. The first is the reminder call: an agent can call a few days and a day ahead, ask whether the person is coming, and offer to move the booking. A moved booking frees a slot the clinic can fill, which is worth more than a passive reminder that is ignored. The second is the booking call itself. An agent that confirms the details and the right phone number at booking reduces misses caused by wrong times and unreachable contacts.
To attribute a change to the agent, compare against a period or group without the calls, and track confirmed, rescheduled and unreachable outcomes, not only the final rate.
Reminder calls are outbound calls. In the United States, the consent rules for AI-generated voices under the TCPA apply to them, and for health care there are further privacy rules about what can be said to whoever answers. Check both with counsel before launching. See appointment setting and the AI appointment reminders use case.
Example
An illustrative month. A clinic books 200 appointments and 18 are no-shows (9 percent). The next month, the same clinic has an agent call everyone 48 hours ahead. Of 200 bookings, 120 confirm, 30 reschedule, 12 cancel and 38 do not answer. Of those 38, 10 do not arrive, so the rate is 5 percent. The clinic also tracks how many of the 42 freed slots it refilled, because a cancellation it can fill costs less than a no-show.