Medical errors, by one count, are the third-leading cause of death for Americans. Surgery mistakes, misuse of drugs or equipment, delays in treatment and the like kill at least 100,000 a year, possibly as many as half a million.

No one knows the exact number, and that points up an underlying problem: Hospitals almost universally resist confessing when a medical error hurts or kills a patient, because admitting fault can expose them to lawsuits. Getting them to overcome this reluctance is essential — to let patients and their families know the truth, and to ensure that hospitals become safer by learning from their mistakes.

The federal government has made only a token, indirect effort to push for greater truthfulness. It demands that hospitals be accredited to qualify for Medicare funds, and the largest accrediting organization, a private group called the Joint Commission, requires hospitals to tell patients or families when something goes seriously wrong. But this rule isn't enforced; hospitals don't lose their accreditation when they conceal errors.