And at the end of five years after all those hours, I felt I had acquired the kind of clinical confidence that comes from having done all the required major and minor operations of my field, and from having participated in the pre-operative and post-operative care of those patients. I finished my residency as a fully trained surgeon comfortable not only with taking out a gallbladder and removing a tumor, but also with operating on the wide range of individuals who might walk through my office door and caring for almost any of their complications or complexities. That level of comfort came from the hours I put into my training and the experiences I acquired.

I agree that exhaustion is not good for residents, or for patients, and that an increased emphasis on patient safety and the importance of sleep is clearly needed in the medical profession. But I can’t help but wonder if we may also risk losing something by trying, prematurely perhaps, to fit the unpredictability of the illness experience and the individuality of human relationships into a scheduling grid that has little proven efficacy.

Some of the Institute of Medicine’s recommendations are simply part of good patient care. Supervision by experienced physicians is always critical, and the more supervision, the better. It makes sense, too, that we need to pay close attention to the process of transferring patient responsibility, the “handover,” and that residents should spend less time with non-educational work, such as retrieving X-rays and scheduling tests.

But it’s unclear to me that we are doing the best by our patients, and ourselves, by reaffirming the 80-hour cap, as the Institute of Medicine committee report has done. Yes, fewer hours overall and a mandatory five-hour sleep break during long shifts would likely be helpful, but we are not even completely sure that setting a weekly limit of 80 hours will do what we think or hope it might do. Instead, perhaps we should put the $1.7 billion dollars per year that would be required for the institute’s recommendations into research first on our current situation.

There is, as the expert panel was quick to concede, little conclusive data on the effects of the current residency duty hour limits. In fact, there have been few, if any, large-scale studies on how strictly residency programs have followed the 2003 mandate; which scheduling adjustments have worked, or have not; how the quality of resident education might have been affected; and, most importantly, exactly how patient safety may or may not have been compromised.

As Dr. Michael M. E. Johns, chairman of the expert panel, remarked at a public briefing on the report on Tuesday, “While the science on sleep and human performance provided a rich evidence base for duty hour adjustment, there was limited data on the impact of the 2003 limits on actual hours worked, scheduling practices, education and patient safety.” In other words, in the realm of resident duty hours reform, there isn’t really enough information to make solid evidence-based recommendations.

In fact, the much-touted cap of 80 hours is hardly based on scientific evidence or extensive testing. In a letter last year to The Journal of the American Medical Association, Dr. Bertrand Bell, who was crucial in getting residency reforms passed in the 1980s, wrote, “The specific ’80-hour week’ was actually determined by a colleague on my porch and was based on the following informal reasoning....” That reasoning included, as Dr. Bell continued in the letter, the idea that “it is reasonable for residents to work a 10-hour day for 5 days a week [and] it is humane for people to work every fourth night.” After a series of mathematical calculations, his colleague came up with the now hallowed figure. And “eureka,” Dr. Bell wrote, “that equals an 80-hour week.”