Dear Gemba Coach,
Actually, on this specific question, I do: don’t do it. I’ve seen many lean “houses” over the years and just by Googling “TPS house” you’ll probably find more. In my experience, such efforts are about implementing lean in the company, not helping the company to become lean – and rarely pay off. There are two main issues to consider when adopting the TPS house: firstly, how and why it actually came up within Toyota and secondly how these concepts translate out of Toyota and in your own organization.
As John Shook has pointed out, one should not confuse the Toyota Production System and Toyota’s system of production: TPS is fairly different from what Toyota actually does on its production lines. It sounds fairly close, you’ll say, and I have to agree. TPS shows the way to perfection, the True North. Toyota’s system of production is the set of actual practices that Toyota has in place right now – which evolves according to events and local competence. Any Toyota plant is only as good as its plant manager.The point is that the Toyota Production System house is Toyota’s — not your company’s –and making your own is likely to not make much sense culturally and induce misunderstandings you’ll later rue. Use the TPS house as a way to explain what lean is about and how Toyota does it but don’t try to design your own – that’s missing the point.
The ambiguous term “system” has also caused a lot of lean heartache over the years. Bear in mind that we all tend to interpret what we see from our own pre-existing perspective. Understanding any artifact from the point of view of its creator is often difficult, as can be experienced when we look at any new piece of art or technology.
Our traditional industrial perspective is clearly Taylorist. We’ve been brought up to believe that if we design the right process and we apply it across the board, we’ll get the right results. Logically, it’s easy to interpret the concept of “production system” as a set of processes that need to be standardized across all operations. In this mindset, lean means replacing our existing processes by “leaner” processes – and it makes sense to systematize these lean processes in a roadmap, house, manual, etc.
When Toyota pioneers dreamed up their system, they were working from a very different premise. Their obsession was kaizen, not systematization of processes. From this perspective, a system meant “a set of interrelated activities to improve quality, cost, lead-time, and productivity.” It was NOT a set of actual production processes, but a box of homework exercises that, if practiced assiduously, would lead to improved processes. There is no such thing as a lean process: opportunities for further kaizen can always be found. The activities summarized in the “system” give a clear direction for the next step of kaizen:
- Customer satisfaction — Oddly, but quite revealingly, this aspect often disappears from adapted houses. The first exercise to work on in order to become lean is to improve customer satisfaction. To start with this means striving to deliver good parts on time: no quality complaints, no late deliveries. Sure, this can be achieved by holding an inventory and lots of quality inspection, which is exactly what Toyota engineers do when they’ve got a doubt about a process: they put finished goods inventory and add inspection operators, with the explicit aim to kaizen it away. For any company, asking oneself what would customers complete satisfaction look like is the key to getting everything else right.
- Jidoka — The jidoka pillar is probably the most original part of TPS and the hardest to understand because it blends a certain understanding of quality with a vision of the relationship between human work and machine work. To take one aspect of it, the homework exercises are about built-in-quality. No step in the process should accept bad parts, make bad parts or pass on bad parts to the next step. The basic exercise is to stop whenever any defect has been identified (by either the operator or the machine) and investigate until the cause of the defect is found and eradicated. This will lead you first to eliminate human errors, due to not following standardized work, then to work with manufacturing engineering to eliminate causes of defects in the way machines are designed and finally to improve product design so that less defects can occur, at which level one can accurately speak of “build in quality.” There are a number of technical tricks to do so, from andon to poka- yoke, but the main idea is to practice the activity of “stop and investigate at every defect” in order to learn about what causes defects.
- Just-in-time — The favorite pillar to most industrial companies, JIT is about learning to deliver exactly what has been ordered exactly when it has been ordered and in exactly the right quantity. The emphasis is on “exactly”; no less, no more. Now, this turns out to be quite a challenge, because production systems are usually conceived to be kept running (for labor cost and equipment payback considerations) regardless of technical issues or part shortages. Forcing oneself NOT to produce more than immediate demand BUT not to accept to produce late is very demanding and mechanically involves reducing batch sizes and stabilizing processes. THERE IS NO JUST-IN-TIME PROCESS in the abstract. Or, more to the point, every process has its level of just-in-time: month? week? day? hour? You start with what you’ve got, level the plan, reduce the batch size and fight each production loss until you increase your level of just-in-time.
- Standardized work and kaizen — Involving operators in designing or redesigning their own work stations has been a Toyota obsession from very early on. Indeed, in the first published paper about TPS, the authors highlighted two major distinctive features of the production system: just-in-time production and respect for humans, meaning that workers are allowed to display in full their capabilities through active participation in running and improving their own workshops. The underlying mechanism to do this is to practice standardized work and kaizen relentlessly.
There is not ONE version of the Toyota house, but several according to when and by whom it is drawn. Some place heijunka along with standardized work and kaizen on the base. Others insist that there should be a further basic step of “stability.” The French plant came up with 5S, TPM, and problem solving as a base below standardization and kaizen. Since Fujio Cho formulated the Toyota Way 2001, 10 years ago, some houses now have kaizen and respect as their basic pillars, and so on. I’ve just seen one with “finding waste and problems” at the top and “visual control and flexibility” as the base. All equally correct.
The point is that the Toyota Production System house is Toyota’s – not your company’s, and appropriating it through making your own is likely to 1) not make much sense culturally and 2) induce misunderstandings you’ll later rue. Use the TPS house as a way to explain what lean is about and how Toyota does it, by all means – we certainly all refer to it frequently, but don’t try to design your own – that’s missing the point.
The point of the house is that certain activities can be performed independently of industry or job, whether in engineering, production, purchasing (maybe even sales?), etc. For instance, getting to the next level of just-in-time is pretty much like saying: lose weight by walking faster and exercising more often. Fair enough. The details of how Toyota actually practices this are very industry specific (there’s nothing quite like automotive) and Toyota specific. They can inspire, but copying the results of years of practicing just-in-time or jidoka improvement will NOT deliver anything for your own business. At best, you’ll invest in implementing stuff on the shop floor no one will ever know how to use properly.
On the other hand, it’s hard to fight city hall, so if management wants it, you’re going to have to comply sooner or later. In this case, I’d suggest:
First, try to get the management group to formulate clearly what they want out of the lean efforts – the test method so to speak. For instance, if we take Art Byrne’s list from Wiremold (in Lean Thinking) this would be something like:
- 100 percent on-time delivery,
- 50 percent defects reduction every year,
- 20 percent productivity gain every year,
- 20x inventory turns,
- a visual workplace utilizing 5S.
Getting agreement on something like this and getting this on paper is key to your success and can rekindle the deeper argument of how to become lean.
Second, stay as close as you can to the basic TPS house seen as improvement practices:
- Customer satisfaction must be improved on quality, cos,t, and lead-time,
- Start with safety and morale,
- Just-in-time levels must be improved from month, week, day, hour, minute etc.,
- Jidoka must be improved by better visualizing problems and responding right away rather than working around them,
- Workstations must be improved by getting operators to standardize and improve constantly how they work.
DO NOT try to fit all tools and practices to help people make sense of the “toolbox.” This is a common mistake and it’s incomplete, confusing and encourages precisely the wrong kind of thinking.
- Third, as your company is taking its lead from Toyota by creating its own production system, make sure to insist that the “system” formulation is never permanent in Toyota, but subject to rethinking and evolution. The “Toyota Way” was termed the Toyota Way 2001 to explicitly make the point that this was what Toyota thought in 2001 but that it should be seen as a signpost on the journey, not the ending.
The one consistent feedback on translating TPS into other companies is that first, companies pick and choose which aspects they think will work for them, and ignore the others. You can see this easily by comparing how often just-in-time is attempted or written about to how rarely jidoka gets mentioned.
Secondly, firms will “adapt” the tools and principles to make them more palatable to the local culture. Most plant managers will actually argue this point vehemently.
Twenty years of experience show that both tendencies are a sure recipe for disappointing, indifferent results. TPS works first because it’s a system, and you can’t ignore a part of it any more than you can choose tables with only the left legs, and secondly, it delivers when you adapt yourself to it, not the other way around. This is exactly what Toyota has done, as it continues to struggle to be better at customer satisfaction, just-in-time, jidoka and standardized work and kaizen, and THAT is the example to copy and take heart from.