The country is deep in winter, but attention again is returning to that summertime phenomenon dubbed “the July effect.” That’s the name given to a supposed spike in medical mistakes and poor patient outcomes at teaching hospitals during the seventh month of the year, when newly minted MDs start providing care.

Numerous studies have reached conflicting conclusions about the extent of the July effect and whether it even exists. A massive study of spinal surgery outcomes published Jan. 29 online further complicates the picture, finding that patients going under the knife at teaching hospitals in July largely fare just as well as their counterparts during the rest of the year but do slightly worse on a couple of metrics.

My latest. Read the whole shebang.