Examples of sigma use abound in the product manufacturing world. Screws and nuts really work together because product and process designers worked hard to make sure that the part variation, sigma, was held to a minimum. The concept of sigma's use in the service sector is harder to visualize. If we don't understand why we should use sigma, our use of the tool is slim. Not only do we have to use and understand sigma, additionally we must understand the science associated with its use. (From Chapter Two: Why Sigma?) So explains James Abbott in this guide for executives who want the benefits of...