July: a time of sweltering heat, fireworks-related injuries, and newbie doctors roaming the halls of teaching hospitals, ready to learn medicine by practicing on you. The "July Effect"—the idea that medical mistakes spike in that month because new, inexperienced residents are on the scene— has become the subject of repeated studies trying to sort out whether it's real or just conventional "wisdom." Those studies have reached differingresults. So, should we believe the newest one, which attributes a 10 percent July spike in fatal medical errors to those freshmen docs? The study by David Phillips and Gwendolyn Barker, to be published in the Journal of General Internal Medicine, has a large sample size going for it. Phillips says that many prior "July effect" studies have examined just a single hospital's population. But:
He and Barker, by contrast, probed a national database of more than 62 million death certificates that spanned from 1979 (when hospital status was first recorded in those records) through 2006 (the most recent year for which data were available). They turned up almost a quarter-million deaths that were coded as having not only occurred in a hospital setting, but also been due to medication errors. Both in-patient and out-patient cases were included [U.S. News & Report].