A physician shortage is fast-approaching. According to the Association of American Medical Colleges, the US is projected to have a shortfall of up to 121,300 physicians by 2030, owing to population growth and the increased needs of a rising percentage of seniors who will require more doctors.

Linda Green, the Cain Brothers & Company Professor of Healthcare Management, has a fix for the looming crisis, and it boils down to two words: increased efficiency.

“There is definitely a perception that there is a physician shortage, and there is definitely a reality of a physician shortage in certain geographic areas, particularly rural areas,” says Green, who teaches in the division of Decision, Risk, and Operations. “But what I addressed in my research is that the conventional way in which prior analyses were conducted was entirely wrong.”

Green’s insights are gaining renewed attention as policymakers look for ways to avert the forewarned crisis, with Green appearing on television to discuss the issue. Her work in this area is one of many examples of how she has bridged research with practice over a four-decade career, taking the big view on the complex and often chaotic world of hospital operations to improve efficiencies and reduce costly waste.

A professor at the Business School since 1978, Green is now conducting a deep dive into the field of healthcare delivery innovation in preparation for her keynote address at the annual INFORMS conference this October, where she intends to highlight the big impact issues emerging in the quickly evolving healthcare environment that may benefit from operations research analyses.

“There is a growing interest by researchers in our field in tackling problems that will have substantial impact,” Green says. “The whole healthcare system is changing dramatically because of technology, new kinds of professionals, and new delivery and payment methods. These present major challenges and opportunities that all the healthcare systems are dealing with.”

Pooling

The looming physician shortfall is an example of those big issues. The forecasted crisis is based on a traditional physician-patient ratio of 1:2500, but in a widely cited article published in Health Affairs in 2013, Green and her coauthors identified operational improvements in the delivery of care that have the potential to completely offset the projected increase in physician demand.

In the article, Green shows how if primary care providers team together in shared practices, they can collectively handle a larger pool of patients. Grounded in mathematics, the proposal is illustrated by a scene at the grocery store’s checkout aisle. If the entire line is handled by one register, then everyone can be held back by one tedious price check. But if one line is handled by multiple registers—as happens at Trader Joe’s, for example—then one delay only delays one person, as the other registers continue to process the line.

In the same way, Green’s analysis found that a pool of three physicians can provide primary care to hundreds more patients than three physicians operating independently, while still assuring timely access. Nationally, if all US physicians pooled into teams of three, and if, in addition, just one in five patient visits received care through an e-visit or from a nurse practitioner or physician assistant rather than from their primary care doctor, then the number of required full-time physicians nationwide drops by one-third, which would resolve the forecasted physician shortage.

Queueing

A queueing expert, Green has authored dozens of research studies proposing many ways to reduce delays throughout the healthcare field.

In a recent paper published in Medical Care Research and Review with Nan Liu of Columbia University’s Mailman School of Public Health, Green used queueing theory to demonstrate how reducing elective C-sections in New York City hospitals to more closely adhere to World Health Organization guidelines would lead to large savings in bed capacity, and hence costs. In another prominent paper published in Operations Research in 2008, Green and Sergei Savin, a former faculty member of Columbia Business School who is now at Wharton, developed a mathematical model to demonstrate how medical practices can increase productivity and revenue by sizing their patient panels to reduce no-shows (estimated at up to one-quarter of all appointments).

“Once physicians heard about this, we got a huge number of requests for this paper and requests to consult on this,” says Green.

But implementing operational improvements is a whole different challenge, she adds. Green cited a 2005 study she conducted with New York–Presbyterian Hospital to reduce emergency department delays. By changing physician staffing based on a queueing analysis that considered the highly variable patient arrival streams over the day and over the week, the hospital decreased the proportion of unseen patients by 23 percent even while patient arrivals increased 6.3 percent and provider hours increased only 3 percent. Within a year, however, physicians reverted to their old staffing system.

“The physicians didn’t like the new schedules, so they just changed them back,” says Green.

While a system rife with inefficiencies can sound maddening, it’s also been an endless source of research interest for Green. As how the physician Atul Gawande popularized the simple yet revolutionary idea of hospital checklists in his book The Checklist Manifesto, so has Green pointed the way forward for significant hospital improvements at little to no cost.

“Very few hospitals have done any work to analyze the patient flows and figure out where are the bottlenecks,” Green says. “It’s a culture thing and it’s a leadership thing. There are hospitals that have made huge changes, and usually it’s because there has been a concerted and extended effort by the leadership in conjunction with the physicians.”