Those who reported mistakes were surprised to learn that, except in situations in which they had been clearly reckless, they were praised, not punished. Dr. Henry Otero, an oncologist, made a report after being told by a colleague that he had failed to spot the low magnesium level of a patient. “I missed it,” he told a newspaper. “I didn’t know how I missed it. But I realized it’s not about me, it’s about the patient. The process needs to stop me making a mistake.

