Erring on the side of over-caution is another matter. A classic example was beta-blockers, which an American Heart Association study said will "lengthen the lives of people at risk of sudden death due to irregular heartbeats." The beta-blockers in question were available in Europe in 1967, yet the FDA didn't approve them for use in the U.S. until 1976. In 1979, Dr. William Wardell, a professor of pharmacology, toxicology and medicine at the University of Rochester, estimated that a single beta-blocker, alprenolol, which had already been sold for three years in Europe, but not approved for use in the U.S., could have saved more than 10,000 lives a year. The type I error, erring on the side of over-caution, has little or no cost to FDA officials. Grieving survivors of those 10,000 people who unnecessarily died each year don't know why their loved one died, and surely they don't connect the death to FDA over-caution. For FDA officials, these are the best kind of victims -- invisible ones. When an FDA official holds a press conference to announce its approval of a new life-saving drug, I'd like to see just one reporter ask: How many lives would have been saved had the FDA not delayed the drug's approval?
The bottom line is, we humans are not perfect. We will make errors. Rationality requires that we recognize and weigh the cost of one error against the other.