I have had a long and somewhat tortured fascination with regards to this topic and other similar questions. In terms of background when I returned to the United States from Japan in the mid 1990′s after working for Toyota Motor Corporation it was difficult for me at least to recognize many of the efforts that were supposedly modeled after the Toyota Production System (TPS). Some of it was frankly bewildering. The Lean movement has gone through many phases and efforts and I am certain that this will continue. I have commented in speeches, articles, and other areas over the past ten years about why I think Lean is different from the Toyota Production System and what are some of the causes for this dissimilarity.
Honestly however it would not bother me if Lean were different from TPS and managed to achieve sustainable results (or improvement that is the real key over time not just sustaining) while developing people. Unfortunately I do not see this happening very often. And when I see it happening it tends to be very local in nature and highly dependent upon a select group of people that understand it well and practice it consistently.
As Michael Balle pointed out in his response you need a certain critical mass of people to become both versed and skilled in the topic in order to improve and sustain those improvements. Unfortunately I do not see that occurring in most companies attempting Lean principles. Instead companies tend to become fixated on items like” tools” (value stream mapping, standardized work, A3 reports, etc.). Or they create unfortunate but well intended “rules” for people to follow. Neither case will necessarily produce results (let alone sustained or improved results) over time for multiple reasons. Sometimes I derisively call this the Lean wallpaper approach where lots of neat looking things are posted on walls but there is very little to show in the way of actual results.
The latest shift in Lean over the past few years has been to put more emphasis on the “thinking” and “managing” aspect of TPS as a solution to the reality that not many companies attempting lean are succeeding. This adjustment is a piece of the puzzle but it will not be the magic elixir either. We can pontificate about Lean principles, the scientific method, experiments, excellence, etc. but in some fashion we are just moving from “shop floor wallpaper” to fancier “management wallpaper” and comfortably distancing ourselves from the reality of the shop floor (i.e. genba) in the process.
Unfortunately just saying smart things does not make us perform better just as hanging the basic laws of thermodynamics on the wall does not necessarily make the average person a better physicist. The Lean movement tends to talk about the “map” rather than the “actual terrain” and how to get from point A to point B. Both have value but if physical progress is the goal eventually you have to put the map down and start moving in the intended direction. A compass (i.e. a tool) of course helps on your journey as does the concept of True North (a principle) but eventually you run into actual mountains, or rivers or other barriers that have to be crossed in order to get to your intended destination. The compass or dogmatic concept is no longer so useful in knowing the best way to proceed. Alternatively another way of saying this is that the Lean movement has a fascination with “know what” type of knowledge but not “know how” type of knowledge when in reality both are required. Let me give you a fictitious example I sometimes recite.
A piece of production equipment (a lathe in this case but substitute whatever you are most familiar with) is not performing well on the shop floor. It is only up about 68% of the time, produces over 5% scrap, and has some other associated problems. This single machine is causing lots of associated problems in terms of excessive over-time, quality complaints, and on-time delivery problems for a certain product line. The first lean experts visited and held kaizen events to improve flow, the pace of production to the customer, and moved many things around in the spirit of improvement. Things looked better and indeed were cleaner but the lathe unfortunately still did not run very well.
A couple of years later the next set of lean experts visit the site and said the answer was to standardized the work, draw a value stream map, conduct a 5S event, or implement a pull system, etc. and this would generate improvement . However performance of the lathe or area still did not substantially improve. In other words they were stuck at a very wide river without a way to make good progress.
The next lean expert who visited a couple years later said the key was to emphasize principles like “build-in-quality” or to execute “jidoka” in terms of thinking on this machine. This expert is conceptually right but in reality does not know how to fix the lathe either…so the team retreats to the conference room and considers either “problem solving” or “experiments” for example. That is always a comfortable approach especially from the confines of the meeting room where we can produce more management wall paper about how to cross the river. Of course good problem solving efforts often will eliminate at least some of the problems if the company has some skill in this area. Just as often however the problem solving or experimenting can go sideways and produce nothing but frustration.
Finally a couple years later a retired 65 year old man from Toyota named Tom is called in to look at the lathe. He is honest and says that he knows very little about paint, plastics, welding, or stamping or other areas. He did not bring along a fancy map but he has a lot of practical knowledge about lathes including this particular one. He asks a strange question i.e. “What is your problem?” …The team fumbles around with the question and states that they want to be lean, standardized, level, scientific, and excellent, etc. In other words they talk about how they want to be described rather than how they will get across the river. Finally one person says we need to get to 90% uptime on this machine and less than 0.5% scrap. Tom asks some questions about the material hardness of the part, the tooling program, the cutting tool and a few other items. Armed with a dial indicator gauge Tom makes a few basic measurements on the machine (the actual terrain) and points out that the adjustment gibs on the machine are worn and unfortunately will either need to replaced or shimmed in the short term for a temporary countermeasure.
He also points out that the lathe’s main spindle run out is 50 microns which is eating up most of the tolerance of the part and hence causing most of the scrap. A spindle head in Toyota has about 5 microns of run out. He insists that the bearings in the spindle head be replaced and proper preload be set on the bearings upon re-assembly to improve the run out measurement. He also suggests changing the rake angle of the cutting tool and altering the position with respect to the part mid-line. Finally he chastises everyone for the oil and hydraulic leaks and insists they be fixed as well, etc.
The Lean team is puzzled by his recommendations but with his guidance implements what he suggests and lo and behold the machine now runs at 95% uptime and now has a 2.0 Cpk in terms of process capability and makes virtually no scrap. The machine runs better than ever and the area performance kicks up a notch as well. The team learned a few things in the process as well. Of course there are other problems galore elsewhere on the site. Everyone is happy though for the moment so the teams asks Tom to be their adviser on these other areas but being an modest man he says “No I probably can’t help you much over there. For starters I don’t know those other machines very well. Also you will learn more in the long run if you fix them yourself.”
This fictional situation mirrors a large segment of the Lean movement today. A cluster of people like to run workshops and produce “change”. Unfortunately the change is not always for the better nor does it sustain or develop people. Some people attempt to counteract this by copying the tools or rules of Toyota and assume that using the tools or rules will produce the same results. Unfortunately this faith in tools or rules does not necessarily fix the problem either.
Still others (and I fall into this trap as well) then advocate the distant intellectual safety of promoting problem solving, kaizen, critical thinking, excellence, the scientific method, or whatever spin or flavor of the moment we put on the topic of improvement in conjunction with Lean principles. There is a certain smug moral certainty associated with this position but I think it also comes dangerously close to intellectual sophistry. We can say neat abstract things that sound great on paper but in the end those words don’t produce improvements or build capability either (i.e. hanging the laws of thermodynamics on the wall problem). Being high level and vague also lacks practical specificity on the shop floor (e.g. how to fix the lathe’s spindle run out situation or other problems).
In the end as Michael points out only people produce change and sustain or improve the results over time. You need a critical mass of people that have both the right thinking patterns (know what) but also the right technical knowledge (know how). I think the Lean movement has made some real progress on the former dimension of “know what” in the form of principles, tools, frameworks, kaizen, scientific method, etc. over the past 20 years. Unfortunately I don’t see as much advancement on the actual technical “know how” dimension of the equation and until that problem is solved actual performance results will not match up with the associated performance expectations.