" In summary, both Ford and Ohno followed four concepts (from now on we’ll refer to them as the concepts of flow): Improving flow (or equivalently lead time) is a primary objective of operations. This primary objective should be translated into a practical mechanism that guides the operation when not to produce (preventsoverproduction). Ford used space; Ohno used inventory. Local efficiencies must be abolished. A focusing process to balance flow must be in place. Ford used direct observation. Ohno used the gradual reduction of the number of containers and then gradual reduction of parts per container. The "

― Eliyahu M. Goldratt , The Goal: A Process of Ongoing Improvement