What is TLS? The Synergy of ToC, Lean and SixSigma


Chris HOHMANN – Author

TLS stands for Theory of Constraints, Lean and Six Sigma. TLS is meant to be the combination of 2 or all of these…philosophies, approaches, methodologies, you name them.

I discovered Lean (but we didn’t call it Lean then) and Theory of Constraints at the same time, when I joined a Yamaha Corp. subsidiary in 1989. Even so I gathered more experience with Lean, I used ToC principles and rules when relevant. Six Sigma came later but without surprise as I had been extensively trained about Statistical Process Control (SPC) long before Six Sigma gave it a new shine.

I used TLS without knowing it and came across concept and acronym only in the 2010s while reading Reza PIRASTEH and Kimberly FARAH’s paper “The top elements of TOC, lean, and six sigma(TLS) make beautiful music together” ( May 2006, APICS Magazine) and Bob SPROULL’s “The Ultimate Improvement Cycle” (CRC Press, 2009).

My “discovery” of TLS was nothing more than conceptualization and confirmation of what I have experienced by myself and found natural: using what the three components of TLS had to offer as a powerful synergy.

Introduction to TLS

This slide show provided by Philip MARRIS, CEO of Marris Consulting will give you an introduction to TLS.


View Christian HOHMANN's profile on LinkedIn


Approach, philosophy or methodology?


Chris HOHMANN – Author

We hear and read them often in relation with our preferred body of knowledge*, among which Theory of Constraints, Lean and Six Sigma are the most popular: the terms “approach”, “philosophy” and “methodology”.

I wonder if people use them purposely or as synonyms and I prick up my ears each time an expert explains Theory of Constraints (ToC), Lean and Six Sigma is not this or not that.

Paying utmost attention to the sense of words, especially in English which isn’t my mother tongue, I decided to make some research of my own about what is what and when to use it.

A chose the Macmillan online dictionary and found this:

  • Approach (noun): a particular way of thinking about or dealing with something
  • Philosophy: a system of beliefs that influences someone’s decisions and behaviour. A belief or attitude that someone uses for dealing with life in general
  • Methodology: the methods and principles used for doing a particular kind of work, especially scientific or academic research

No surprise, these terms are not synonyms. Yet there is a certain relationship that I see as concentric circles:

Philosophy as a system of beliefs and knowledge provides a global influential framework. Approach is a focused way to deal with something, largely influenced by the philosophy. Consistently, the proper Methodology helps Approach dealing with something by providing methods and tools.

Philosophy is more about abstraction and knowledge, thinking and attitude while Methodology is action focused. Approach is somewhat in between and links Philosophy to methods and tools, or thinking and attitude to doing and action, if you will.

Fine, so what are ToC, Lean and Six Sigma for example?

Well, for me first they are systems of beliefs backed by tangible proofs and knowledge. They influence my way of thinking and consider things. When I have to deal with a situation, an issue, I am influenced by this system and it formats they way I will approach it. Of course I will use the methods and tools ToC, Lean and Six Sigma provide in a certain way**, which is my approach.

**Using ToC, Lean and Six Sigma in combination or synergy is referred to as “TLS

So to answer the question what are ToC, Lean and Six Sigma, my answer is they are what you make them! They can be either Philosophy, Approach or Methodology or a combination of the three.
Therefore, in my opinion, nobody is wrong using any of these words as qualifiers, but the choice should be made with care for the sake of clarity.

Assuming only few people really pay attention to the meaning of the words, I think most people use them alternatively as synonyms. I dare ask what they mean if I feel necessary to clarify.

Adding to the confusion with Body of Knowledge and Paradigm

Sometimes we also come across Body of Knowledge and Paradigm. What do these words mean?

A *body of knowledge (BOK or BoK) is the complete set of concepts, terms and activities that make up a professional domain (http://en.wikipedia.org/wiki/Body_of_Knowledge)
BoK is shared and accepted by a community while a philosophy can remain personal.

Paradigm is a formal set of ideas that are used for understanding or explaining something, especially in a particular subject. It is a windows through which watch things or a prism through which seeing and understanding something.

“Prism” is purposely chosen as the point of view can be biased or distorted.

Best example is probably the world of cost paradigm vs. world of throughput paradigm, where the proponents of the second see the biases of the cost paradigm.

Bandeau_CH36Feel free to comment and/or correct this post. If you like it, share it!

View Christian HOHMANN's profile on LinkedIn


You don’t give me answers, you ask me questions

He’s a former colleagues of mine I worked with during 10 years. Let’s call him Jack. He’s about 10 years younger, cocky, went from graduation directly to consulting and as he stated himself one day, “can’t stand being unable to answer a client’s question right away”.

The opposite of me in many aspects and that’s perhaps why we worked well together for so long. The biggest differences between us are that I have no problem to admit I don’t know and I manage silence rather well.

What long flattered and puzzled me about Jack was his repeated “compliment”: You don’t give me answers, you ask me questions.

Well, this is what managers are supposed to do: help their staff to find answers and solutions. Even a manager is not supposed to have answers to all questions, but he should at last know how to tackle problems.

The questions I asked Jack were for both of us. They were a way to structure my own thinking about the issue as I didn’t have the answer myself. The questions were the logical loud spoken path to put pieces together, check the assumptions, simplify the problem and try to craft a possible solution or at least a satisfactory answer.

Asking questions was an invitation for Jack or others to join the exercise and connect our brainpower together. I could make believe I knew the answers but played it old wise man leading his mentee to find the correct answer by himself as a part of his initiation. But no, asking question is still my quiet and indirect way to say “I don’t know but I am willing to help you find the answer”.

Knowing Jack, it was a wonder he didn’t disregard me for being so openly ignorant, but on the contrary he kept seeking my questions.

Over the years, bits of explanations surfaced. One of them was I was a cool manager not giving direct orders (command and control) but helping his teammates to learn. Something so basic in my opinion it does not deserve any praise.

What Jack never said in such way but appeared to me recently (and still is an assumption) is that asking questions and logically analyzing the problem together, I simply showed him respect.

I did not care about my rank nor image, I gave a hand when asked for, worked with lower ranking associates, admitting I didn’t know. Furthermore, for highly educated and intelligent people it was a sign of respect not to throw them any answer but encourage them to analyze, try and solve by themselves.

Reflecting on my own experience, I’ve seen so many managers who couldn’t stand not to know and gave just any answer and left you on your own with it.

How many would I compliment for their managing skills?

No so common after all.


View Christian HOHMANN's profile on LinkedIn

Goal-focused gemba walks


Chris HOHMANN – Author

Most of the gemba walks are done with a large spectrum search for improvement, usually focusing on the 7 wastes known as “muda”. Some practitioners will look for variability (“mura”) and unreasonableness (“muri”) as well.

Yet as improvement opportunities are always infinite and resources are not, this broad approach may divert precious resources on secondary or even irrelevant objectives relatively to the organization’s Goal.

Just as commanders in military operations, managers should focus on main objective(s) in order to leverage action instead of risking to deplete their resources and fall short to achieve their objectives.

Therefore managers and executives should Goal-focus their gemba walks, which means look for deviations that hinders the organization to achieve its Goal or improvements that truly contribute to achieve the organization’s Goal. And this is significantly different from picking up any improvement opportunity.

>Lisez-moi en français


There are two high-level roadmaps that can be combined* to help: the Goal Tree and Hoshin Kanri. Both describe the cascade of intermediate objectives that are necessary to achieve in order to achieve the top-most objectives, hence the Goal.

*read the article “How Goal Tree can help Hoshin Kanri

My preference goes to Goal Tree. A full Goal Tree is a collection of benchmarks and an assessment tool altogether.

>Learn more about it

With the Goal Tree and all the Necessary Conditions not yet fulfilled in mind, the gemba walker has a checklist of items to look for.

On the gemba, the basic question is then: “is this process/activity/task a Necessary Condition?

  • if no, the next question is: “why does it exist? / can it be suppressed?” If it can’t be suppressed it must be adjusted to consume the very minimum resources
  • if it is a Necessary Condition, the next question is: “is this process/activity/task contributing to achieve the Critical Success Factors and the Goal?”


  • if yes, it means the status is green*, then improvement is probably needed somewhere else,
  • if no, if status is amber* or red*, the process/activity/task is a good candidate for improvement.

*read the article “Goal Tree: how to assess Necessary Conditions status?

Only with the Goal in mind and knowing the cascade of necessary conditions, a gemba walk will truly focus on meaningful improvement opportunities. Otherwise it is easy to start cleaning up the whole mountain when getting the rocks out of the path would be enough.

About Gemba walks pitfall, you may like Go for the why, not for the who (don’t look for someone to blame)

If you liked this post, share it!

View Christian HOHMANN's profile on LinkedIn

Goal Tree explained by Bill Dettmer

A Goal Tree, sometimes still referred to as Intermediate Objective Map or IO Map, is primarily a Thinking Processes tool, itself a kind of subset of the Theory of Constraints. The top of the Goal Tree is a strategic planning tool while going down to its bottom links strategy to operations.

In this video, Bill Dettmer explains the Goal Tree

Bill Dettmer’s quote from the interview, (The Goal Tree is):

The standard against which you evaluate reality to determine whether you’re doing well or not. Call it a set of metrics if you will.

Another quote from the interview:

As long as the Goal of the system doesn’t change (…) this tree doesn’t change. It could be good for five or ten years. (…) So the effort to do one of those trees is well invested because once it’s done, you can use it again and again to analyze progressively how you’re doing in the system.

Indeed, building a Goal Tree is not a quick and easy exercise. You may read it in my testimonial series: the Goal Tree chronicles.

About the authorIf you liked this post, share it!

View Christian HOHMANN's profile on LinkedIn

Ten tricks to get things done

Many action plans share the same problems, they expand with additional todos but little gets done. Here are 10 tricks to change the wish list into real action plan that delivers.

1. accept only important and urgent actions

Setup a basic rule to filter out proposed actions or suggestions. A severe one would be for instance “anything that is not urgent nor important isn’t worth to be put on this type of action plan”. Give it some thinking. Unimportant and no urgent items will only clog the board.

If unimportant and no urgent ideas or suggestions are worth giving a later consideration, prepare a separate list.

2. accept only actions people can carry out themselves

As a manager, accept only actions people can carry out themselves. This means they have authority to get them done or the skills and resources – including time – to carry out the actions. If they haven’t but actions are necessary nevertheless, start a different action plan under the responsibility of someone having authority. These actions will have to be carried out by someone else, like maintenance  or support team, a subcontractor, etc.

3. limit the capacity of action plan

In order to prevent team members writing long wish lists, limit the capacity of the action plan. 3, 5 or maximum 10 lines is best.  This doesn’t mean the management refuses to hear problems or improvement suggestions, but as the plan capacity is limited, it is obvious that only meaningful actions will find their way onto the plan and actions need to be carried out quickly in order to free space for new ones.

4. every action has someone accountable for

Every action must have someone who takes ownership and accountability. This does not mean this person has to do it him/herself, but make sure action is taken by someone and objectives will be met on due date.
Do not accept orphans, that is actions without owners. There is a saying: “giving to all is giving to nobody”, in other terms if you wait for someone to spontaneously pick up the action you may wait a long time.

5. place the action plan in full sight of everybody

With action plan in full sight of everybody, Anybody can monitor the progress, hence the pride of actions’ owners and accountables will get some extra motivation. People that depend or suffer from a situation that needs solution or improvement may be demanding and challenge the ones in charge.

6. review plan every day

Such plans are suitable for Management in Short Interval, ideally everyday. Besides, urgent and important things require close-loop management. Daily reviews encourage real action as constant attention is kept. People usually want to succeed in their undertakings and constant attention gives extra motivation.

7. accept solutions not excuses

When actions get delayed or face difficulties, people in charge should propose alternate solutions or due dates, not excuses.

Make this rule clear from the beginning and stick to it firmly.

8. if plan is full, a new action needs an older one to be dumped

Another important rule is to keep the plan’s limitation. If there is no place left but a new action should be taken into account, there are only 2 options:

  1. wait until one action is completed and leaves the plan
  2. remove one action which wasn’t completed so far. Maybe it was not that urgent and important after all?

9. planned actions are perishable: out after ten days!

Linked to the previous trick, consider actions as something perishable. If one action could not be completed within 10 days (2 working weeks), it wasn’t probably urgent nor important. Dump it and free space for a new one. This rule will add some pressure to the group and help keep momentum.

10. escalate

The last trick is to escalate actions judged important and urgent but couldn’t be accomplished within the 10 days. Find sponsorship with somebody that has authority to allocate additional skills or resources. Let this option remain an exception, otherwise it would be too easy to push things to others.

Bandeau_CH12If you liked this post, let it know, share it!

View Christian HOHMANN's profile on LinkedIn

Is 3D printing the ultimate postponement? Part two

In the previous post of this series, I used somewhat extreme examples to illustrate the benefits of postponement with additive manufacturing i.e. 3D printing (space exploration, ships amidst oceans and warfare). In this post I use more common examples about how the promises of these new techniques will disrupt existing businesses and bring new benefits to competitors and customers.

Spare parts for automotive industry, appliances, etc.

Spare parts are needed for mending cars or appliances for example. Until now, spare parts must be produced and kept in inventories in the eventuality someone needs a part. This happens eventually but it is hard guess to tell which parts, when and in which quantities parts will be required.

Therefore, spare parts production is launched according to complex and more or less scientific guessing, based on statistics. Once these parts are produced, they’ll go for various locations through the proprietary network or through  importers, distributors, retailers and repair stations.
Huge amounts of cash are kept frozen in inventories, scattered in many warehouses in various locations.

  • These inventories are likely to grow with each new specification change that affects a part, as the adequate replacement part must be provided
  • These inventories’ value will have to be depreciated when parts become obsolete and the probability of their sales diminishes

Storing and distributing spare parts is a business per se, but the value-added remains limited (which does not mean it is not profitable!), especially for the “players in the middle” who act more like cross-docking platforms taking their share of profits and risks.

Over time distributors and retailers slightly changed their business model and drift away from their original business: storage and retail.

In old days it was important to be the reliable parts provider and huge inventories were normality.

More and more those companies embrace a financial, more profit-driven purpose and keeping inventories is for them a necessary evil at best. Distributors and retailers try to get delivered at short notice in order to keep inventories – that is frozen capital and risk – low.

They push the problem upstream to manufacturers, the latter being required to reduce delivery lead time, which most often ironically means holding inventories to serve “off-the-shelf”. Distributors and retailers become a kind of post-office collecting orders, passing them over to manufacturers, who in some case have to deliver to the point of use, by-passing the distributor/retailer.

I worked in some industries facing this “problem” and the distributor / retailer channel in this way does not seem sustainable as manufacturers try to get rid of these “order collectors”.

Now with the rise of additive manufacturing techniques, new opportunities appear. Distributors and retailers may use them to become manufacturers themselves. What they need are competencies to use such equipments and managing CAD files from OEMs’ libraries, “print” spare parts at will: at the right moment, in the right version, without holding huge, costly and risky inventories of parts in huge warehouses, with high fixed costs.

Furthermore, customizing parts locally would yield additional revenue, as customers with specific and maybe urgent needs are willing to pay a premium.
So would scanning and redesigning no longer supported parts for which no CAD files are available.
This kind of service is an ultimate postponement because the manufacturing of parts is on hold until the very last moment, when the orders are confirmed or the parts paid!

This is one example about additive manufacturing (i.e. 3D printing) techniques can disrupt existing businesses and bring new benefits to (some) competitors and customers. The financial barriers to entry dropping significantly, OEMs could reconsider to re-integrate this kind of activity and keep the value creation all by themselves.

This post being a prospective analysis, I would be glad to read your comments.

If you liked it, please share it!

View Christian HOHMANN's profile on LinkedIn

The catalyst

I like this word “catalyst” when talking about “a person whose talk, enthusiasm, or energy causes others to be more friendly, enthusiastic, or energetic”.

We don’t use it currently in French even so the meaning is the same, we’ll talk about “moderator”, “facilitator” or “coach” instead.

Yet “catalyst” is much more how I felt recently with a small group of participants in a workshop. It was expected by my client to be a kind of kaizen event with a clear goal and limited time: in three days design the layout of a future streamlined assembly line.

It took me the first morning to get basic knowledge about current operations, difficulties and stakes of a company and a business I was discovering.

Being the alien, I asked many questions the insiders kindly answered. Those questions had a double benefit:

  1. give me the minimum necessary insight
  2. force the ops guys working with me to reflect about my questions

When we returned to the nearby office, I organized my new “knowledge” on several sheet of paper in order to summarize, memorize and understand as well as let the participants check my understanding.

During the shopfloor tour and my summing up, some of them had questions and surprises, which found their place on a paper sheet as well.

During the two and half days left, I asked many more questions, made some suggestions and did what I am good at (say my colleagues): sort out and arrange all the popping ideas and scattered data and facts to get a simple and clear understanding of the situation.

Doing so, the participants found most of the time themselves what to do next and how to do it. From time to time, some direction in form of question or suggestion from my side restarted again the stuck team.

In the evening of day two, the line was not only designed, it was 60% installed thanks to all spare furniture and equipment we scavenged. Two weeks later the first assemblies went out of the new line.

This result was unexpected according to the CEO and the group participants, as turning ideas into actions always was difficult in this company.

This was achieved by the subject matter experts themselves, I was “only” their catalyst which helped to unleash and focus their potential talents.

A role that fits me.

Bandeau_CH6If you liked this post, share it!

View Christian HOHMANN's profile on LinkedIn

Introduction to Critical Chain Project Management

Welcome to my introduction to Critical Chain Project Management (CCPM)!

Critical Chain Project Management is a “new” approach to Project Management, with connections to the Theory of Constraints.

While in the 1980s the production management changed from mainly local unit cost control to a holistic approach that encourages flow (Lean), the project management has not significantly changed* since the introduction of the Critical Path Method  in the 1950s (PERT: USA 1954 Polaris program) and despite its recognized weaknesses regarding reliability and meeting deadlines.

*Agile, Lean IT have brought improvements but the Critical Path Method is still the main model.

In the 1990s, Eli Goldratt, author of the famous business novel the Goal, revisited project management with a Theory of Constraints point of view.

In short, he proposed to shift from a task-focused management to a resources-focused management, taking into account their availability and capacity conflicts. To distinguish the new Critical Path from the previous one, he called it the Critical Chain.

The Critical Chain is the longest path taking into account the resources load levelling.

Critical Chain Project Management (CCPM) reviews also how tasks durations are estimated and proposes to set up a global buffer to protect the project achievement on due date instead of protecting every single task.

Here is a brief overview introducing CCPM

another one:

Here is a second video that gets you a bit deeper into CCPM concept

View Christian HOHMANN's profile on LinkedIn

Goal Tree chronicles – The hamster and the tree

Companies in nowadays competition need proactive and engaged people, yesteryear managers are expected to turn into leaders. Despite this general truth and the logical demonstration of required change, some managers just stick to their cosy routine: the hamsters.

In this post:

  • How a “hamster” manager refuses to embrace change required by robust logical analysis
  • At a certain point, dictating the next step is mandatory for company’s sake
  • The Goal Tree is hierarchy independent

The hamster

The scene takes place in a company in which I’ve spent a lot of time to carefully prepare the policy deployment with top management.

As so often, CEO and his C-suite had a clear overall idea where to drive the company for the five years to come, but they had only a vague slogan – and calling it slogan is a compliment – and a few numeral objectives ready. Nothing to overwhelm the lower level employees with confidence and motivation, on the contrary it’ll have all looked scary if communicated as it was.

First we (the consultants team) reworked the slogan and worked out details. I deliberately imposed the Goal Tree as structuring tool, first to my consultant staff, second to the client.

We started to clarify and restate the Goal. That exercise showed the C-suite how unprepared they were to communicate their plans. We spent a (long) time defining the Critical Success Factors and despite my insistence to keep only five or six of these high level objectives, the C-suite insisted on ten.

Once this was done, a presentation was made to management staff, and we (the consultants) went to see the next level of management to further explain the Goal Tree’s logic and ask managers to select the Necessary Conditions they knew/felt which needed improvement so they turn Green in my color status system (i.e. condition is constantly fulfilled).

I personally met one guy with a relatively high position and a long experience in the company. He was credited to be one of the company’s experts and one of the company’s pillars and probably among the opinion leaders.

During our face-to-face, what puzzled me most was his imperviousness towards the Goal Tree, or call it Policy Deployment / Hoshin Kanri principle. He managed to escape proposing anything, sticking to his “good soldier” posture and kept saying: just tell me what to do, I’ll adjust to it.

What a hamster he was!

The hamster is a category of employee as described in the BlessingWhite model of employee engagement.

>Learn more about “hamsters” >Learn more about “BlessingWhite model

This hamster (read manager) was typically enjoying the cosy comfort of his nest (read office) and saw no reason to add any annoyance to his routine. His position granted him some importance and the feeling that he was irreplaceable. While making believe he totally understood the threat of raising competition, all his attitude showed he didn’t care or expected to remain unscathed.

Yet he could not openly fight against the project, therefore he played obedient soldier even not wholeheartedly. “Just tell me what to do, I’ll adjust to it“. So disappointing from a manager at this level.

Not negotiable

The policy deployment was not an option and as it was obviously not possible to win this manager to the engaged camp, I made him clear what the next step was:

  • He had to explain to his staff the global project’s aim and background as well as the top of the Goal Tree (the company’s Goal and the top most objectives supporting its achievement)
  • As he couldn’t (didn’t want to) set contributing objectives for his department, he had to pass the ball directly to the next level and ask for meaningful contributions to achieve the Critical Success Factors directly linked to the department’s activity
  • These proposals must be filed into a standard format and will be reviewed by project’s steering committee for global alignment
  • He as manager was de facto accountable for the carrying out of the approved actions
  • One of the consultant will be present to facilitate the whole thing

This is not negotiable!

It may not be the best example of how to engage people, but in some conditions showing muscles and speaking in harsher tone is simply more effective and adequate.

At that moment I was the boss, empowered by the CEO and legitimate by my position as project leader on the consultant’s side.

The Goal Tree is hierarchy independent

Things went on as planned and the Goal Tree proved once again a robust and hierarchy-independent tool.

Even so the manager in charge of the department did not proactively (“reluctantly” would better fit the reality) support the cascading or “policy deployment”, the staff understood all the Goal Tree’s logic demonstrated, accepted the challenge and proposed relevant improvements.

Summing up

What does this story tell us?

  • (Goal Tree’s) Pure logic and rationality are sometimes powerless when facing emotional or cultural biases, often called “resistance to change”
  • Change management does not imply accepting any opposition as valid and trying to convert every opponent. At some point, “I am the boss” is an appropriate option
  • (Goal Tree’s) Pure logic and rationality often help to convert the mass to embrace the necessary change, even if some opinion leaders fight against it

Chris HOHMANNFeel free to comment or testify. If you liked this post, share it!

View Christian HOHMANN's profile on LinkedIn