A Just-In-Time Approach to Medical Care

A mathematical model helps doctors offer every patient a same-day appointment.
January 18, 2007
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A few years ago, a radical idea began circulating in the world of primary-care management. Rather than scheduling a medical practice in the traditional manner — booking a doctor’s appointments well in advance, while perhaps keeping a few open slots for emergencies — advocates of an approach known as “advanced access” called for offering every patient a same-day appointment, regardless of the severity of the ailment. That way, patients wouldn’t experience frustrating waits of weeks or longer (and potentially suffer the medical consequences of a delay in care). Meanwhile, doctors and their staffs wouldn’t waste capacity by holding appointments open or attempting to triage patients by phone. There would be fewer cancellations and no-shows, and everyone would be happier.

Much to the surprise of skeptical doctors and nurses, researchers have found the approach works. Empirical studies have shown that managed-care and fee-for-service practices that follow advanced access can significantly reduce patient backlogs, and even make more money, by adhering to the approach’s unofficial motto: Do All of Today’s Work Today.

However, the lack of specific implementation guidelines held back doctors who might otherwise have given advanced access a try. Professors Linda Green and Sergei Savin, working with physician Mark Murray, designed a mathematical model that allows doctors to apply the approach to their practices. The researchers’ elegant solution, in the form of a simple-to-use Excel spreadsheet, allows doctors to predict how many patients they can accommodate. “A lot of physicians are trying to implement the idea of advanced access,” says Green. “But they need to find the right balance between patients and capacity.”

Many studies have investigated why the traditional scheduling method makes this balance difficult to achieve. One conclusion is that the longer patients are forced to wait for an appointment, the greater the chance they will cancel. Often, the practice isn’t able to fill in the suddenly available slot, so the doctor’s time is wasted. “The irony is that physicians may have three or four weeks’ of patients waiting for an appointment, but they’re spending only 70 percent of the day seeing patients,” Green says. “With advanced access, the number of no-shows goes down to almost zero. If patients get an appointment for the same day, chances are they’re going to show up.”

At first, advanced access may seem counterintuitive. Typically, doctors try to keep their availability equal to their average demand, reasoning that slow days and busy days will eventually balance each other out. But the flaw in that logic is that excess capacity from a slow day can’t be rolled over to a busy day, and busy days quickly produce an ever-increasing backlog. Since the goal of advanced access is to provide a same-day appointment to every patient who wants one, doctors need to keep their availability greater than their average demand. Green and Savin’s model shows doctors what this difference should be.

Doctors who follow the approach will occasionally need to work some overtime, since the daily demand will vary. The researchers’ model allows doctors to predict how many days they will stay late, depending on how many patients they want to serve — a degree of control not found in traditional practices. “Many doctors work a lot of overtime in a traditional system, and they still wind up with a long backlog,” Green says. “So they try to get nurses to sort out who needs the physician more urgently. They wind up with more administrative overhead. With this system, they’re not wasting time, and they can bring in more revenue.”

This possibility of greater efficiency and profitability has already won over some doctors. Green and Savin have received requests for their model from several large practices, including the St. Francis Hospital and Medical Center at the University of Connecticut and the Carle Clinic Association, which has more than 300 doctors, in central Illinois.

The researchers are distributing the spreadsheet to any doctor who requests it. “From my personal contact with the healthcare system and talking to physicians, I realized this was an area that needed a lot of help,” says Green, who has spent much of her career designing ways for healthcare services to run more smoothly, from increasing the efficient use of MRI machines to preventing emergency room overcrowding. “Healthcare is the biggest sector of the U.S. economy and affects all of our lives. The more I educated myself, the more I realized that problems in healthcare systems really needed an analytical approach.”

Read More

Green, Linda, Sergei Savin and Mark Murray. “Providing Timely Access to Care: What Is the Right Patient Panel Size.” Forthcoming in the Joint Commission on Accreditation of Healthcare Organizations.

Linda Green is the Armand G. Erpf Professor of the Modern Corporation at Columbia Business School and a founder and codirector of the Columbia Alliance for Healthcare Management.

Linda Green

Professor Green earned her doctorate in Operations Research from Yale University. Her research, which has focused on the development and application of mathematical models of service systems, has resulted in dozens of publications in the premier technical journals such as Operations Research and Management Science as well as prominent healthcare journals such as Health Services Research, Inquiry and Academic...

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