Most of us know the difference between effectiveness and efficiency. Effectiveness is doing the right things, while efficiency is doing things right. Their intersection yields high productivity. I even wrote a book about it: Doing the Right Things Right: How the Effective Executive Spends Time. But many people remain confused about the difference between productivity and efficiency. Too often, the terms are viewed as synonyms. They’re not. They’re related but certainly not interchangeable. Indeed, in some cases, they couldn’t be farther apart.