‘Learning to See‘, by Mike Rother and John Shook, was published two decades ago. As far as I know it was the first book to discuss Value Streams.
A Value Stream in Lean is the series of operations that, together with the skilled staff, required equipment and materials, combine to deliver the required product or service. In health care, there are numerous value streams, with many contributing processes.
For example, if a person needs elective surgery for a joint replacement, the value stream would be likely to include processes such as pre-operative assessment; advance education on the joint replacement, and perhaps access to smoking cessation services; admission; a pre-anaesthetic process; the surgical procedure itself; post-operative recovery; mobilisation and rehabilitation, and so on. There are a large number of processes that, in turn, feed in to this, such as diagnostic tests, theatre scheduling and preparation of the theatre including obtaining the correct artificial joint and the right set of instruments.
Rother and Shook’s book describes how you display a Value Stream visually. They do this by taking an imaginary industrial company, and then walking the reader through the process of drawing this on paper. In the course of this, they mange to convey a lot of Lean principles, particularly on value and waste, batching, flow, push and pull systems, scheduling and supermarkets.
Having constructed the current state Value Stream, they use the principles they have explained to then develop a Future State Value Stream, a visual decription of a system with improved flow. This is very well done, and they explain a lot of key terms in the course of their examples.
One of the ideas I had not seen explained in detail before, was Value Stream Loops. In their view at the time, you work to identify the parts of the process that can be managed in flow, with one by one passage of products or patients. Where you cannot produce a continuous process, you join the sections, which they term ‘Value Stream Loops’, mainly by using supermarkets. The final, in flow, process the becomes the pacemaker against which the rate of other parts of the system is synchronised. The striking thing for me was how easy they made it to see how a process was intended to operate, including clear visualisation of flow.
Many of the symbols they describe are still in standard use, including striped arrows to indicate push, symbols for kanbans, kanban post, withdrawal and so on.
It’s not cheap to come by this book, as it is long out of print. Second hand copies run to £60 and over ($80 US). I borrowed a copy from my colleague, Gavin Hookway, and while I might think twice about paying the second hand price for it, if you have the chance to read a copy, then I recommend that you make use of the opportunity. It is an important book, and remains relevant and worthwhile.
Cover image courtesy of the Lean Enterprise Institute.