Abstract
Imagine you are watching a sunset with friends in the early 16th century. Imagine the difficulty you have in challenging their conclusion that the sun revolves around the earth because it does not fit with your latest observations of planetary motion. Which would your friends reject more easily — your observations, or the established view that the earth is the center of the universe? You now have a sense of the difficulty of changing a fundamental doctrine of 20th-century medicine — the idea that early intervention is always the right thing to do.In this issue of the Journal, investigators . . .