A reply is not an attendance. Measure the visit.

How the mechanism works

A reminder works by doing three things: reminding people who forgot, making it easy to say they cannot come, and giving staff time to fill the slot. The second and third matter as much as the first. A reminder that only says “see you tomorrow” misses most of the benefit.

• Sent at an agreed time before the appointment
• One-tap or one-word reply to confirm, reschedule or cancel
• Reschedule requests go to staff as pending
• Freed slots are visible to whoever manages the calendar

Consent and message rules

WhatsApp requires that people have opted in to receive messages from your business, that the opt-in names your business, and that you honour opt-outs. Reminders sent outside a 24-hour customer service window must use an approved message template. Check local rules too, especially for health information: keep reminder content minimal and avoid details a person would not want seen on a shared phone.

Rescheduling without losing the customer

When someone cannot come, offer to find another time instead of only recording a cancellation. Collect a preferred window and pass it to staff, who confirm the new booking. After a missed appointment, one polite message offering a new time is usually enough; repeated chasing hurts trust and message quality.

How to measure it

Use your own records. Take a baseline of scheduled appointments and attended appointments for several weeks before launch, then compare the same measure afterwards, ideally across similar weeks or by running reminders for some appointment types first. Count cancellations that were rebooked separately from those that were lost.

• Attendance rate: attended ÷ scheduled
• No-show rate: missed without notice ÷ scheduled
• Rebooked cancellations
• Slots refilled after an early cancellation

Limitations to state out loud

The Cochrane review covered eight trials with 6,615 participants, mainly SMS reminders, searched up to 2012; its authors called the evidence insufficient to decide policy conclusively. It did not study WhatsApp. Results also depend on your customers, the reason for the appointment and how easy rescheduling is. A confirmation reply only shows intent; people who confirm can still miss the visit, and people who do not reply can still attend.