Differences from TPS

While lean is seen by many as a generalization of the TPS into other industries and contexts, there are some acknowledged differences that seem to have developed in implementation.

1. Seeking profit is a relentless focus for Toyota exemplified by the profit maximization principle (price – cost = profit) and the need, therefore, to practice systematic cost reduction (through TPS or otherwise) to realize benefit. Lean implementations can tend to de‐emphasize this key measure and thus become fixated with the implementation of improvement concepts of “flow” or “pull.” However, the emergence of the “value curve analysis” promises to directly tie lean improvements to bottom‐line performance measurements.
2. Tool orientation is a tendency in many programs to elevate mere tools [standardized work, value stream mapping (VSM), visual control, etc.] to an unhealthy status beyond their pragmatic intent. The tools are just different ways to work around certain types of problems, but they do not solve them for you or always highlight the underlying cause of many types of problems. The tools employed at Toyota are often used to expose particular problems that are then dealt with, as each tool’s limitations or blind spots are perhaps better understood. So, for example, value stream mapping focuses upon material and information flow problems (a title built into the Toyota title for this activity) but is not strong on Metrics, Man, or Method. Internally, they well know the limits of the tool and understood that it was never intended as the best way to see and analyze every waste or every problem related to quality, downtime, personnel development, cross training–related issues, capacity bottlenecks, or anything to do with profits, safety, metrics or morale, etc. No one tool can do all of that. For surfacing these issues, other tools are much more widely and effectively used.
3. Management technique rather than change agents has been a principle in Toyota from the early 1950s when they started emphasizing the development of the production manager’s and supervisors’ skills set in guiding natural work teams and did not rely upon staff‐level change agents to drive improvements. This can manifest itself as a “Push” implementation of lean rather than “Pull” by the team itself. This area of skills development is not that of the change agent specialist but that of the natural operations work team leader. Although less prestigious than the TPS specialists, development of work team supervisors in Toyota is considered an equally, if not, more important topic merely because there are tens of thousands of these individuals. Specifically, it is these manufacturing leaders that are the main focus of training efforts in Toyota since they lead the daily work areas, and they directly and dramatically affect quality, cost, productivity, safety, and morale of the team environment. In many companies implementing lean, the reverse set of priorities is true. Emphasis is put on developing the specialist, while the supervisor skill level is expected to somehow develop over time on its own.
4. Lack of understanding is one of the key reasons that a large share of lean manufacturing projects in the West fail to bring any benefit. In Factory Physics, Hopp and Spearman describe this as romantic JIT, where the belief in the methods is more important than the actual understanding and results. In this aspect, lean manufacturing is more of a religion than a science. Others have compared it to cargo cult science.