The term “overdiagnosis” came into vogue in 2011, with the publication of best seller Overdiagnosed: Making People Sick in the Pursuit of Health, by MDs H. Gilbert Welch, Lisa Schwartz, and Steve Woloshin. As lead author Welch explains in his introduction: “While the term sounds like it means simply ‘excessive diagnosis,’ it actually has a more precise meaning. Overdiagnosis occurs when individuals are diagnosed with conditions that will never cause symptoms or death.” Overdiagnosis matters because the health care system has no mechanism in place for distinguishing between a legitimate diagnosis and an overdiagnosis. As such, an overdiagnosed patient will...