An ongoing agreement among all companies that make up the value stream for a product family to correctly specify value from the end customer's point of view, eliminate wasteful actions from the value stream, and ensure that those actions that do create value occur in continuous flow according to the customer's pull. Once this task is completed, the collaborating companies must analyze the results and restart the process as long as the product family persists. A method to perform the necessary analysis is described in Womack and Jones 2013. 

‍