Any step in the production process that improves the product for the customer. Also, any activity that the customer cars about, that changes the product and that is done right the first time. The value-added concept and value stream mapping approach is very subjective and thereby often causes confusion concerning the underlying science of a process. The value-added concepts were first promoted in the 1990s and became highly popular when Rother and Shook published “Learning to See” in 1998. For further discussion, see “The Value-Added Fantasy” in Factory Physics for Managers.