What if all patients could be seen on the day they call?

The challenge of reducing waiting times is a classic queuing problem in operations research. Professionals in all sorts of service industries, from restaurants and hotels to banks and department stores, have faced it in one form or another. Most of them handle the juggling of clients far better than physicians, despite the lower stakes. Mounting evidence shows that doctors can see patients quickly, too—even in perennially backlogged practices—and that when they do, they benefit themselves and the people they treat.

...

When a patient calls in the morning asking to see a doctor who uses open access, the office offers an appointment for that same day. Why are there openings available? Well, the main reason most doctors defer today's work to some time in the future is that today's schedule is clogged with appointments made weeks ago. Doctors following the same-day scheduling model, on the other hand, are free today because they saw yesterday's patients yesterday. Using open access, doctors might still schedule some early-morning appointments in advance, for follow-up visits or for patients who actually prefer a future appointment. But the key is that they keep most of their time free for same-day visits and fill up their schedules as the day goes.

...

Taking into account the total number of appointment requests is the first step to open access, but it doesn't do the trick on its own. It seems like common sense to balance the number of daily appointment slots with the average daily number of appointment requests. But a mathematical model built by operations researchers at Columbia University shows this intuition to be wrong. That's because demand varies from day to day, and not always predictably. If the average number of appointments is 20, for example, some days there may be 25 and other days only 15. Scheduling 20 slots every day won't work because extra service capacity can't be transferred from day to day: The unused slots from slower days cannot be recouped any more than empty airline seats can be sold after takeoff.

The only solution is to build in a margin of safety in the form of more appointment slots than an average day will ever use. That sounds like wasted capacity, but it's actually more efficient than filling up the appointment book in advance. That's because the further in advance patients make appointments, the likelier they are to miss them. A no-show rate of 30 percent is not uncommon. According to one study, many patients don't understand scheduling systems and find long waits insulting, so they think nothing of missing their appointment without calling to cancel. All these no-shows also add up to waste and lost revenue—the very problems traditional scheduling would seem to prevent. The strange upshot: By juggling too many patients, doctors lose income even as their backlog grows longer and longer.