Every scheduling model is a bet about variance. The question is not which is fastest on a good day, but which one absorbs the case that runs forty minutes over.
The four models
Indian OPD clinics run one of four scheduling patterns, usually without having chosen between them. They differ in who absorbs variance: the doctor, the patient, or the schedule itself.
| Model | How slots are filled | Absorbs a long case by | Fails as |
|---|---|---|---|
| Block | Everyone told the same arrival time | Making patients wait | A full waiting room and no way to triage it |
| Individual (wave off) | One patient per fixed slot | Running late, cumulatively | A clinic that finishes ninety minutes over |
| Modified wave | Two or three at the top of each hour, then singles | Catch-up time inside each hour | Only if the overrun exceeds the hour |
| Open access | Same-day booking, minimal advance | Same-day demand matching capacity | Unpredictable days, and no follow-up structure |
Why modified wave usually wins
It is the only one of the four with slack designed in. Individual slots have none, so a single overrun propagates through the entire session and every subsequent patient pays for it. Block scheduling has slack but spends it entirely on patient waiting time.
The number to watch is not utilisation
A clinic at ninety-five per cent slot utilisation has no capacity to absorb anything, and one complicated case turns the afternoon into an apology. The metric worth tracking is finish-time variance against scheduled close — because that is the one your staff experience and the one that decides whether follow-ups get booked.
Questions we get asked
Which appointment scheduling model is best for an Indian OPD clinic?
Modified wave suits most OPD settings, because it is the only common model with slack built into each hour rather than borrowed from patients or from the doctor’s evening. Individual slots look tidier but have no absorption capacity, so a single long consultation runs late through every subsequent appointment.
Why does high slot utilisation make a clinic run late?
Because utilisation and resilience trade against each other. A schedule filled to ninety-five per cent has nothing spare to absorb a case that runs long, so the overrun has nowhere to go except into the next slot and the one after it. Some deliberate slack finishes the session closer to time than a fuller schedule does.
On the figures in this piece. Every rupee amount above is arithmetic on the assumptions stated beside it, not a market statistic. Where you need published Indian claim data with its source named, that sits on claim data. We publish no figure we cannot show the working for.