The Three Bucket Theory --Dickeson

Take the Wip, for instance. When the materials are committed to a job and move out of Raw inventory, time starts to run on work in process. The Wip clock stops when deliverable product is completed. Wip time is a true measure of production JIT—just in time.

Taichi Ohno taught us to use yellow Kanban cards to "pull" materials through production rather than "pushing" them up into queues. Eli Goldratt teaches us that the rate of production conversion of Raw to Fig is the key to success. In effect, they're both saying that the DMOH of the Wip measures the rate of conversion—the productivity of the enterprise.