A continuing agreement among all the firms sharing the value stream for a product family to correctly specify value from the standpoint of the end customer, remove wasteful actions from the value stream, and make those actions which do create value occur in continuous flow as pulled by the customer. As soon as this task is completed, the cooperating firms must analyze the results and start the process again through the life of the product family. (Womack and Jones 1996, p. 276.)
A method for performing the needed analysis is described in Womack and Jones 2002.