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The July effect

By Kenneth M. Ludmerer


“Don’t get sick in July.”

medical studentsSo the old adage goes. For generations medical educators have uttered this exhortation, based on a perceived increase in the incidence of medical and surgical errors and complications occurring at this time of year, owing to the influx of new medical graduates (interns) into residency programs at teaching hospitals. This phenomenon is known as the “July effect.”

The existence of a July effect is highly plausible. In late June and early July of each year, all interns and residents (physicians in training beyond the internship) are at their most inexperienced. Interns—newly minted MDs fresh out of medical school—have nascent clinical skills. Most interns also have to learn how a new hospital system operates since most of them enter residency programs at hospitals other than the ones they trained at as medical students. At the same time the previous year’s interns and residents take a step up on the training ladder, assuming new duties and responsibilities. Every trainee is in a position of new and increased responsibilities. The widespread concern that these circumstances lead to mistakes is understandable.

Yet, despite considerable consternation, evidence that there is a July effect is surprisingly hard to come by. Numerous studies of medical and surgical trainees have demonstrated no increase in errors or complications in July compared with other times of the year. Many commentators have declared the July effect a myth, or at least highly exaggerated. A few studies have shown the existence of a July effect, but only a slight one—for instance, on the sickest group of heart patients, where even a slight, seemingly inconsequential mistake can have grave consequences. Even here, however, the magnitude of the effect does not appear large, and the studies are highly flawed. Certainly, there is no reason for individuals to avoid seeking medical care in July should they become ill.

That the July effect is so difficult to demonstrate is a tribute to our country’s system of graduate medical education. Every house officer (the generic term for intern and resident) is supervised in his or her work by someone more experienced, even if only a year or two farther along. Faculty members commonly provide more intense supervision in July than at other times of the year. Recent changes in residency training, such as shortening the work hours of house officers and providing them more help with chores, may also help make residency training safer for patients—in July, and throughout the year.

Uncertainty is intrinsic to medical practice. Medical and surgical care, no matter how skillfully executed, inevitably involves risks. It would not be surprising if a small July effect at teaching hospitals does occur, particularly in certain subgroups of critically ill or vulnerable patients, given that house officers are the least experienced. However, the fact that this effect, if present, is small and difficult to measure provides testimony to the strength of graduate medical education in the United States. Indeed, the quality of care at teaching hospitals has consistently been shown to be better than at hospitals without interns and residents. Patients may be assured that their interests will be served at teaching hospitals—in July, and throughout the year.

Kenneth M. Ludmerer is Professor of Medicine and the Mabel Dorn Reeder Distinguished Professor of the History of Medicine at the Washington University School of Medicine. He is the author of Let Me Heal: The Opportunity to Preserve Excellence in American Medicine, Time to Heal: American Medical Education from the Turn of the Century to the Era of Managed Care, and Learning to Heal: The Development of American Medical Education.

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Image credit: Multiracial medical students wearing lab coats studying in classroom. Photo by goldenKB, iStockphoto.

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