Maxing Out on Primary Care

The projected physician shortage can be averted by tapping non-physician medical staff and electronic communications.
November 27, 2013 | Research Brief
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The Idea

The projected physician shortage can be averted by tapping non-physician medical staff and electronic communications.

The Research

With an aging US population, greater prevalence of chronic diseases, and more than 25 million Americans expected to receive health insurance through the Affordable Care Act by the end of the decade, many experts anticipate a severe primary care physician shortage on the horizon. Most of these estimates are based on simple and commonly used ratios, such as one physician for every 2,200 patients.

But Professor Linda Green knew from previous research that the number of patients cared for by a physician — the patient panel size — depends on not only who the patients are — for example, their ages and prevalence of chronic disease — but also how physicians practice and the desired level of access to timely medical care.

Green, along with Sergei Savin of Wharton and doctoral student Yina Lu, applied a queuing model they developed to create a more realistic estimate of the predicted primary care physician shortage based on new patient care models that are already being implemented by many practices and assuming that 80 percent of patients can get same-day or next-day appointments.

Practical Applications

Medical Practice Office Managers, Operations Managers

While previous estimates of the shortage assumed all primary care practices operate as solo practitioners, only about 18 percent of physicians currently practice alone. Instead, large practices where doctors share the patient load are becoming the norm, and other medical professionals, like nurse practitioners and physician assistants, are increasingly being used to provide care that doesn’t require a physician. Practices are also using more electronic communications — including answering non-urgent patient questions, such as how to treat a common cold or a pulled muscle, or even managing routine aspects of a chronic condition — through personal health records and e-mail, so that office visits aren’t necessary.

Green and her co-researchers demonstrated that combining the pooling effects of physician teams with offloading demand to non-physicians and utilizing the less time-consuming process of answering patient questions electronically has the potential to increase the number of patients per physician from the current average of about 2,200 to up to 5,000, while assuring timely access to appropriate care. The researchers found that in order to totally eliminate, in the aggregate, the predicted primary care physician shortage, patient panels just need two physicians who can cover for each other when a patient’s primary physician isn’t available and 20 percent of the total care provided by nurse practitioners or addressed by electronic communications.

Linda Green is the Armand G. Erpf Professor of the Modern Corporation in the Decision, Risk, and Operations Division at Columbia Business School.

Read the Research


Green, Linda, Sergei Savin, and Yina Lu.

“Primary Care Physician Shortages Could Be Eliminated Through Use Of Teams, Nonphysicians, and Electronic Communication” Health Affairs: Vol. 32, No.1 (January 2013): 11-19.


Green, Linda, Sergei Savin, and Mary Murray.

“Providing Timely Access to Care: What Is the Right Patient Panel Size?” The Joint Commission Journal on Quality and Patient Safety: Vol. 33, No. 4 (April 2007): 211-8.


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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