FOR decades, scientific research has shown that annual physical exams — and many of the screening tests that routinely accompany them — are in many ways pointless or (worse) dangerous, because they can lead to unneeded procedures. The last few years have produced a steady stream of new evidence against the utility of popular tests:

Prostate specific antigen blood tests to detect prostate cancer? No longer recommended by the United States Preventive Services Task Force.

Routine EKGs? No use.

Yearly Pap smears? Nope. (Every three years.)

So why do Americans, nearly alone on the planet, remain so devoted to the ritual physical exam and to all of these tests, and why do so many doctors continue to provide them? Indeed, the last decade has seen a boom in what hospitals and health care companies call “executive physicals” — batteries of screening exams for apparently healthy people, purporting to ferret out hidden disease with the zeal of Homeland Security officers searching for terrorists.

In 1979, a Canadian government task force officially recommended giving up the standard head-to-toe annual physical based on studies showing it to be “nonspecific,” “inefficient” and “potentially harmful,” replacing it instead with a small number of periodic screening tests, which depend in part on a patient’s risk factors for illness. Faced with such evidence, I have not gotten an annual physical since around the time I finished my medical training in 1989. I respect my doctors, but I see them only when I’m sick. I religiously follow schedules for the limited number of screening tests recommended for women my age — like mammograms every two years and blood pressure checks — but most of those do not require a special office visit.

“There’s a lot of inertia and unwillingness to let things go — it’s hard for doctors and patients,” said Allan S. Brett, professor of clinical internal medicine at the University of South Carolina, who tells well patients there is no need to see him annually. “I’ve rolled back the frequency and intensity of screening over the years, absolutely. I’m not doing lots of things now, because there’s no evidence that they help.”