The article in the Harvard Business Review by Steven Spear and H. Kent Bowen titled “Decoding the DNA of the Toyota Production System” was very interesting and insightful. Toyota has been well-known for its quality for many years, but its system has been hard to emulate for many companies. The authors think this is because managers of other companies who have toured and studied Toyota plants often confuse the system with the tools and practices they see. I believe the authors have provided good reasoning for their contention that they have uncovered the “DNA” or the four necessary rules for successful adaptation of the Toyota Production System within other companies.

The first rule states that “all work shall be highly specified as to content, sequence, timing and outcome.” This, of course, is why the system appears to be so rigid. There is a step by step process that must be followed at all times. Any deviation in the process is considered an issue that must be resolved. This rule is intuitive, so it is not surprising to me.

Even though the second rule is contrary to conventional wisdom as to how most other manufacturing plants operate, it does make sense. It states that “every customer-supplier connection must be direct, and there must be an unambiguous yes or no way to send requests and receive responses.” Everything about that customer-supplier connection must be standardized — the actual request itself, the form and quantity of the product, and the time involved to complete the request. There must be a specific person involved on each end of the customer-supplier connection each time that connection takes place.

The third rule states that “the pathway for every product and service must be simple and direct.” Again, work flows from a specific person or machine to another specific person or machine. This rule is probably the most counterintuitive when I think of the design of most production lines, where the flow of goods and services is dictated by the availability of people or machines. However, I can see the benefit of doing things this way because the root cause of a problem can be more easily and quickly identified when there is a specific person or machine involved.

The fourth and last rule states that “any improvement must be made in accordance with the scientific method, under the guidance of a teacher, at the lowest possible level in the organization.” The authors describe the Toyota Production System as having created a “community of scientists” who use the scientific method to make improvements. The scientific method promotes the type of experimentation that leads to optimal results. With their supervisor acting as teacher, the workers who actually do the work are the ones best suited to develop and conduct these experiments.

In conclusion, the authors have made a good case for their decoding of the Toyota Production System process into four rules. Even though there have been some companies who have used Toyota’s system successfully (Jayaram et al., 2010), the authors point out an important paradox which makes it hard for others to wrap their hands around these four rules. It’s the paradox of having a precise, rigid system in combination with flexible procedures that make improvements in processes and activities. As the authors say, “it is the continual response to problems that makes this seemingly rigid system so flexible and adaptable to changing circumstances.” It’s what sets Toyota apart from other companies not successfully employing the Toyota Production System.