The "flow or "value-stream" perspective represents a shift from vertical to horizontal thinking, Horizontal thinking means looking across the traditional vertical structures of functions and departments to connect activities in the stream of the value flowing from suppliers, through the organization, and on to customers. In other words, concentratiritg on overall flow means focusing on system efficiency rather than just on the point efficiency of individual elements in an organization. 4Flow is enabled when materials and processes ar6 standardized across the supply chain to reduce complexity.