Kaizen or Rework?
Part 1 of 2

A letter to Bill Gaw from Jim Womack

Dear Bill,

I recently visited a contract electronics manufacturer with a striking capacity for kaizen  the steady improvement of every step along its key value streams. Dozens of kaizen events were being performed across the company to eliminate wasted steps and to remedy quality, availability, adequacy, and flexibility problems in each value stream. At the same time, kaizen teams were trying to speed continuous flow and to perfect pull systems when flow was not possible.

The managers were pleased with their work and I had to admire both their technical skills and their enthusiasm for rapid improvement involving the employees touching each value stream. However, I noted that most of the value streams being improved were for products that had been launched recently. I wondered why so much kaizen was necessary.

Indeed, I pondered  as I often do these days  whether the kaizen effort was analogous to old fashioned end-of-the line quality inspection in mass production organizations. Value streams for new products were being put in place without much thought to lean principles or much rigor in thinking through the details of every step and action. Kaizen teams were then inspecting the processes once in operation, finding them far from lean, and launching waves of corrective action.

Given that many bad practices had been built into the value streams, these kaizen efforts were necessary and highly productive. But why wasn't the organization performing lean process design as an integral part of the development process? And was the organization's skill in after-the-fact kaizen  that is, its talent for process rework -- actually reducing the pressure for the hard conversations about lean process development that ought to be taking place during product development instead?

As I've reflected on this situation, I've wondered if the practices of Toyota and other lean pioneers have been misunderstood. Kaizen is an important activity at Toyota and involves all employees. But new processes launched at Toyota are usually extraordinarily lean to begin with and post-launch kaizen is a small part of Toyotas competitive advantage.

The secret lies in Toyota's product/process development system that focuses on creating "profitable operational value streams"  to use a favorite phrase of the late Allen Ward. These streams have been thoroughly "pre-kaizened" by examining every step in the proposed production and fulfillment process long before launch.

The first step is to make sure someone is responsible for thinking about the whole process needed to bring a new product from order to delivery. By thinking about the production process at the same time the product design is being evaluated, it's possible to optimize both.

The second step is to lay out the process on paper and consider the different ways that it might be conducted. For new types of products requiring new processes it is particularly important to consider a number of different ways the whole process and each step might be conducted and to conduct simple experiments to see which way works best. (This is the process development analogue of the Set Based Concurrent Engineering methods used to evaluate different approaches to the design of the product. It's also a key element in the 3P Production Preparation Process now conducted by advanced lean organizations.)

The third step is to test any new ways of conducting process steps with simple prototypes  even cardboard mock-ups -- to learn how well they actually work. (Another element of 3P.) The knowledge gained from these experiments then needs to be written down and turned into the experience curves of the sort Toyota develops from experiments with simple prototypes of new products.