"In almost every area of human endeavor, the practice improves over time," says Microsoft co-founder Bill Gates. "That hasn't been the case for teaching."
Hm... every area of human endeavor? What's most like teaching, or the process of education? Raising your own children. Has practice improved over time in that endeavor? How about creating and living in communities? How do our metrics look there? Helping people lead healthy lives? I think I read something once about an epidemic of obesity and diabetes (to pick one area). Caring for the elderly and dying... we getting better at that? Creating art? What are the numbers on high achieving painters and poets? Are you a better cook than your grandmother?