The Principle of Flow and Pull

by Chris Butterworth of S A Partners

Too often the principle of flow and pull is seen as applicable only in a manufacturing environment. In fact, the principle can be applied in many different ways. On a recent trip to Kenya I had the pleasure of experiencing the "Matatu" bus service in Nairobi. It really got me thinking about the principle of flow and pull. 

The system is very different from my hometown in Sydney, which has a very similar population size to Niarobi. In Sydney, buses are on a fixed timetable, readily available to look up on various travel apps and published at each bus stop. Buses are frequent and you can even track your bus’s real-time location on your phone. Like most big cities they are more frequent at peak hours, but despite this, are often full during these hours and relatively empty off peak. 

So is this a good example of pull and flow? At one level, buses are pulled through at peak times to match customer demand based on historical demand patterns. Flow is dramatically improved through the use of dedicated bus lanes. Car drivers watch enviously from the queue of their stationary vehicles as buses shoot down the near empty bus lane. Occasionally frustration takes over better judgement, and a quick burst down the bus lane provides the thrill of movement and the often-illusionary progress as you are forced to wait to be allowed back into your lane a few hundred meters further on. If you are really lucky you also avoid the fine.

So there is some pull and certainly better flow for the buses than for the cars. Outside of peak times, the bus system is definitely more push than pull, with fixed timetables pushing out buses regardless of actual demand. 

The system has recently gone cashless, which saves a huge amount of time in collection and counting of cash, and generally works very well. All you need to do is make sure you buy an electronic card and keep it charged up with virtual cash and all is well. That is unless you are a new visitor to the city and unfamiliar with the bus drivers’ inability to accept cash. I recently witnessed an incident with a tourist family trying to board a bus. English was not their first language, and the driver struggled to explain that just giving him more and more money would not work. 

A couple of passengers tried to help – even by offering to use our cards, but you can only use them once on each journey. So after a lot of shouting and gesticulating from the driver, they eventually gave up and will hopefully be able to have a great laugh about the whole experience once they get home—which will hopefully not be by bus. So the electronic payment is intended to improve flow, and generally does, but it was pushed on to the customers, many of whom would still prefer to use cash.

Now back to Nairobi. There are no timetables, few marked bus stops out of the main central boarding points, and you struggle to track your bus’s location on your phone. The buses are small and take about 20 people - sitting down. I boarded a bus and took a seat. Luckily I knew it was the right bus because I had a guide. Also there was a very helpful man with a sign who stood on the pavement saying where the bus was going and encouraging passersby to catch it. 

After five minutes, I wondered what time we would set off. My helpful guide shrugged his shoulders.

"It depends," he said. I decided to practice the five whys and get to the root cause of why we had been waiting. “Well,” says my guide, "the bus is not full."

Eventually my root-cause analysis revealed we would not leave until every seat was occupied. Now other passengers started to join in and promote the virtues of the bus by shouting enthusiastically out the windows to anyone showing the slightest interest. We quickly had every seat full and were off. 

A conductor came to collect our fare and asked where we wanted to be dropped off. We picked a well-known building on the bus route a short walk from our hotel and paid a fraction of a Sydney bus fare. It was cash only and calculated based on how far we traveled. The atmosphere on the bus was fantastic. It was a tight fit, and it was impossible not to get to know your fellow passengers. Sydney buses tend to be silent with people buried in their phones and not knowing where to look. We had a great laugh on the Matutu with everyone sharing a smile and enjoying the experience. 

So is the Matatu a push or a pull system? In one respect it's definitely batch and queue with customers waiting for the full bus or "batch" to be completed before the journey can start. My initial reaction was that this is not a lean system but on reflection I realized it has its advantages.  

  • Its top customer value is cost and it certainly delivers on this by only travelling when full utilization is very high and cost per journey is very low. 
  • Fewer buses are needed in the fleet, saving on capital and maintenance costs.
  • At peak times the wait time is very short as buses fill quickly.
  • In off-peak times there are fewer buses driving around empty and are only pulled through based on demand.

So whilst the departure and arrival time may be a little more uncertain than the Sydney system, overall the Matatu provides a great solution that minimizes cost and provides customer flow with on-demand pull. "Kenyan time" has a bit more flexibility than Sydney time, but then it only takes one accident in Sydney for the whole timetable to get disrupted. 

We need to ensure that we design our flow and pull systems to maximize customer value. Different customers value different things, and we must be careful not to try to impose one-size-fits-all in our systems design. Both the Matatu system and Sydney system work well in different contexts and both have elements of flow and pull. 


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“Medical Taylorism:” An Article that Does a Huge Disservice to Needed Healthcare Transformation

By Dr. Patricia Gabow and Ken Snyder

The article, “Medical Taylorism,”[1] by Pamela Hartzband, M.D. and Jerome Groopman, M.D., in the New England Journal of Medicine, reflects a major misunderstanding of the principles and practice of the Toyota Production System, or Lean as it is often called. Specifically, the article appears to conflate poor implementation with the underlying principles. Several commentators, including many from the Lean community, have weighed in on this debate, but more needs to be said given healthcare’s need for transformation and the powerful solution that Lean offers in this transformation.


Doctors Hartzband and Groopman are feeling pain due to their experiences. We sympathize with their pain. Too often, whether in healthcare or other settings, we see poor implementations of Lean. These poor implementations are almost always due to failure to follow the principles of operational excellence.

In this discussion about Lean in healthcare, there are some specific principles that deserve emphasis. In citing these principles, we will adopt the terminology used in the Shingo Model.[2]

  • Seek Perfection
  • Respect Every Individual
  • Control Quality at the Source
  • Embrace Scientific Thinking
  • Create Constancy of Purpose

It is unfortunate that many who implement Lean seem to forget these core principles. It is hard to imagine any set of principles which would more closely align with the needs of healthcare and commitment to the population’s well-being than these principles.

KPIs are Dead, Long Live the KBIs!

Project succeeded?

About a year ago, the head of logistics and purchasing asked me to carry out some observations on the floor. Their new ERP system had been implemented about two years ago, and he wanted to know where knowledge was still lacking so he could use the information as input for a training plan. So off I went to talk to some of the employees. I asked an employee to tell me exactly what she did while she was working on something, a bit like TV-chef Jeroen Meus. "And now I change this printer to the correct printer ... This has been wrong in the system for a long time." She felt no regrets to report the issue and get it solved once and for all, instead she solved the problem herself on a daily basis. And she was certainly not the only one I noticed doing this during my observations. The employees certainly knew what the final output should be, but they were less concerned about how it should be achieved, or even how efficiently it should be achieved. Is this the behavior and the consequent results you want to achieve as an organization?  

Hoshin Kanri: Translating “Big Vision” from Strategy to Execution


Rick Edgeman, Research Director

Shingo Institute, Jon M. Huntsman School of Business, Utah State University


Tel. +1 435-535-5015                        Email: This email address is being protected from spambots. You need JavaScript enabled to view it.



 Part 1: Hoshin Kanri - Concept Origins

Published March 1, 2016


Prior to World War II, the U.S. share of the world export market was approximately 30%. In the aftermath of World War II that share grew to more than 70% - a result of a generally healthy and educated workforce, as well as a U.S. infrastructure that remained largely untouched by the war. In contrast, many European and Asian nations were left to deal with infrastructure devastation and human tragedy alike, often with less educated workforces using antiquated equipment.


Create Constancy of Purpose 

by Mark Baker

Mark Baker will be teaching the Discover Shingo Model™ Workshop at the 28th International Conference this April

 Published February 3, 2016

When I was a young mechanical engineer at Honda Motor Company, Mr. Honda was still alive and he used to always say, “Unless we have 100% of the people in the organization engaged in making the company better, we will never be able to realize our true potential.” I remember hearing this for the first time, and over the years I have found it to be a great insight, but the real question now is how is this achieved? Mr. Honda’s statement hits on two key points of building a successful organization, namely engagement and alignment. Without both of these aspects, success will be hit or miss.

Mistake-Proofing Mistakes

Written by Bruce Hamilton, President, GBMP

Published January 21, 2016

There is a popular lore provided by Shigeo Shingo that the original name for mistake-proofing (poka-yoke) was “fool-proofing” (baka-yoke). Shingo chided managers at Panasonic for using the latter term, as it was disrespectful to workers, essentially calling them fools. Shingo substituted the word “fool” for “mistake,” because, as he aptly noted, making mistakes is part of humanity. “Mistakes are inevitable,” he said, “but the defects that arise from them are not.”

Notwithstanding Mr. Shingo’s admonitions, however, I still hear the term “fool-proofing” used regularly, and occasionally with a little more venom, “idiot-proofing.” No doubt, these derogatory terms, along with others like “screw-up” and its less gentile derivatives, have given a bad name to one of the most energizing, empowering and creative tools from the TPS toolbox. 

Continuous Improvement from Where It Counts

Written by the Shingo Institute Staff

Published December 21, 2015

“What’s the difference between the Shingo Prize® and other similar awards?” It’s one of the questions most frequently asked of the Shingo Institute. The short answer is that it isn’t just a framework for management. The Shingo focus is on organizational culture conducive to having improvements come directly from the mind of every associate at the organization to get measurable, world-class results.