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Theory of Constraints Versus Lean Six Sigma

Six Sigma – iSixSigma Forums General Forums Methodology Theory of Constraints Versus Lean Six Sigma

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  • #54308

    Lehigh
    Participant

    Are the two approaches to problem solving complimentary or contradictory?

    If complimentary where do the methodologies fit together?

    Does anyone in industries such as healthcare, mining, product development or services have any experience using both methods together?

    I attach an example of work that I have done using both approaches.

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    #194733

    Katie Barry
    Keymaster

    @kelehigh Take a look at some iSixSigma.com articles that focus on TOC but include discussions of LSS: https://www.isixsigma.com/methodology/theory-of-constraints/

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    #194741

    Several articles on 6ToC, the merger of LSS and ToC, have been published in Quality Progress. If you are an American Society for Quality member you can find them at http://www.qualityprogress.com. I have not found the approaches contradictory any more than you could call Lean contradictory with SS. Just remember that SS is about reducing variation that results in defects, Lean is about reducing waste (and defects are just one of the causes of waste), And ToC is about optimizing the process within it’s current constraints then reducing constraints in order of primacy.

    That said, I find that all three work together for process improvement but I am not convinced that anyone has proposed a coherent methodology for doing them all at once.

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    #194742

    MBBinWI
    Participant

    Don: I would disagree on the emphasis of TOC. It’s not to optimize a process, rather to identify the constraint (our friend Herbie). Then, depending upon what form of constraint Herbie ends up being (too much variation, waste, company policies, etc.) you will evaluate and address with the proper tools. There will always be a Herbie, and one of the critical choices is whether the constraint is properly located and all other process steps have the appropriate reserve capacity. Perhaps the biggest failing in management programs is that EVERYTHING should be optimized to reduce all reserve capacity. This is the fundamental failing of many Lean projects. It is not waste to have appropriately sized reserve capacity to support your chosen constraint. This is where the TOC perspective is helpful, in understanding that there must be a constraint and that all other process steps need to be subordinate to that constraint (in other words, must never cause that constraint to slow/stop – which generally requires reserve capacity).
    In addition, the Thinking Processes, part of the larger body of knowledge that Eli developed, provides a useful framework for breaking paradigms around some issues.
    These methods are both complementary and contradictory. Complimentary in the way that a toolbox with various tools allows the user to select the appropriate tool for the task. And contradictory in the way that, should one choose a screwdriver to try to solder some copper tubing, the job will not be succesful (wrong tool for the job).
    In my humble opinion.

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    #194749

    The systems are highly complementary.

    Lean and SS are ways of improving your production. However, applying improvements at different points across the process can result in the overall process throughput getting worse. Only correctly addressing the constraint reliably results in overall process improvement. From a TOC perspective, improvements at a non-constraint are likely wasted effort.

    TOC identifies where to apply Lean / SS methods. There’s a lot more to TOC, but that’s my take-home.

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    #194760

    MMBinWI and an Mike86, your points are well taken. As I read him, Golddratt didn’t say that you MUST optimize within the current constraint but that it is better to do so while the constraint exists and any other changes that do not address the constraint won’t make much difference.

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    #194762

    Lean Six Sigma will help you deal with delay, defects and deviation. TOC will help you deal with constraints which may not cause delay, defects or deviation.

    In Six Sigma, for example, companies spend thousands training Green and Black Belts and tens of thousands getting them up to speed, but often fail to provide them with Six Sigma software to do their job. This is a dummy constraint. For a few hundred dollars they can provide every belt with Excel-based software to be effective in their job.

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    #194764

    MBBinWI
    Participant

    Don: Got to disagree that Eli didn’t say you need to optimize the constraint. Steps 2, 3, and 4 are all about optimizing the constraint. What Eli didn’t do was advocate precisely HOW to optimize, and that’s where Lean, Six Sigma, TPM,and other continuous improvement methods apply.
    I would also disagree that addressing issues with non-constraints won’t make a difference. Waste is waste and wherever it is eliminated will make a difference. It just won’t increase throughput, which is what Eli focused on.

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    #194767

    Eric Lawson
    Participant

    Agreeing with MBBinWI: Maximizing throughput (T) by exploiting the constraint is the main thrust in TOC; so yes, you MUST optimize the constraint as far as TOC is concerned. Also, elimination of waste outside the constraint is presumably a decrease in operating expense (OE) and/or inventory (I). The primary aim of TOC is to maximize T. It also strives to decrease OE and I as long as T is not impacted negatively. So, we are quite consistent with Lean in this regard.

    One thing that I am wary of in Lean and in Six Sigma projects is that the bulk of them seem to be geared toward cost reductions. I like TOC’s emphasis on maximizing Throughput based on the idea that this is where the most meaningful gains can be made for the business (the system). It’s all about work flow baby! And here too, Lean tools and techniques mesh well with TOC.

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    #194774

    Bob Sproull
    Guest

    TOC and Lean Six Sigma are not complementary, all three form an integrated approach (a.k.a. TLS) to improvement. TOC provides the necessary focus by which LSS accelerates improvement. I’ve been using this approach for the past 15 years and the results tell me that this integration is superior to all other approaches to improvement.
    Bob Sproull

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    #194775

    Chris Seider
    Participant

    @ras8202 I assume you mean they ARE complementary? I’ve used both together to increase production lines capacity and output beyond my client’s dreams.

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    #194776

    Bob Sproull
    Guest

    No Chris, the way I intended my comment to read was that I didn’t consider them as complementary, but rather they should be integrated. I hope I didn’t come across as being negative because that was not my intent. I only use the three of them as though they are a single improvement methodology. In my second book, The Ultimate Improvement Cycle, it’s exactly the point I make and I demonstrate their integration as three concentric circles (i.e. one for TOC, one for Lean and one for Six Sigma).

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    #194777

    Chris Seider
    Participant

    Gotcha…to me it’s just a nuance.

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    #194778

    Eric Lawson
    Participant

    @ras8202, @cseider

    Nuance maybe…but an important nuance. Complementary means they work well together. One enhances the other. To put them together in an integrated approach – as a single improvement methodology – is to leverage their complementary relationship.

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    #194779

    Bob Sproull
    Guest

    OK Eric, if that’s your definition of complementary, then I agree with you. My definition doesn’t infer that they are integrated.

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    #194780

    A good point. And now I have to put another book on my Wish List.

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    #194781

    Eric Lawson
    Participant

    @ras8202

    Normally I wouldn’t get hung-up on a word but in this case it is central to Mr. Lehigh’s orginal question.

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    #194782

    I would recommend two books “The Ultimate Improvement Cycle.” & “Epiphanized” to anyone interested in how to combine Lean, 6Sigma, & TOC.

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    #194783

    Lehigh
    Participant

    “Epiphanized” describes how the 3 approaches could be used in a practical sense in a business novel. Thanks to Bob Sproull who recommended that I also read the book by William Detmer, “The Logical Thinking Process: A Systems Approach to Complex Problem Solving”, I was able to put together an approach after much more research that I call Sytemic CPI that I then tested with DLA’s Energy and Aviation groups. When we were able to show that we could deliver the results that we were looking for I wrote the paper, “Systemic CPI for Strategy: Integration of Lean Six Sigma with Theory of Constraints–a new and better method to improve services processes”. I might be able to post it here if anyone is interested (it is about 2.4 MB in size). It is really a cook book approach as to how one starts out with a client gathering requirements together with what I call symptoms and issues and how one could use the ‘Thinking Processes’ to structure an approach to be able to segment a complex services situation into a series of smaller projects that together when executed resolve the customer’s issues completely.

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    #194784

    Eric Lawson
    Participant

    I am quite interested in Systemic CPI for Strategy. Thanks @kelehigh.

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    #194794

    Mike Carnell
    Participant

    @kelehigh I have been following this for a while and stayed out of it basically because I think these types of questions are esoteric and a waste of time. When you ask a question like this so you can talk about your “new system” it is called self promotion. Even though that is not supposed to be allowed we will ignore it because it is a minor point compared to the rest of your post.

    You claim you have a “cookbook” to a “thinking process.” That is an oxymoron at best (more than likely BS as well). Cookbooks do not promote thinking they stifle it. You feed someone a step by step approach and nobody needs to think. This the same way people were taught to dance following footsteps stuck to the floor. You know the steps and you have no intuitive feel for the music. My wife is Cuban and a great natural dancer. They don’t count steps they have a feel for the music and just dance. Cookbooks are Arthur Murray methodology.

    We have seen about a decade of Belts cranked out of certification mills who have been taught tools as a cookbook and still have no clue what DMAIC is. Since you engaged in some self promotion so will I (mine is legal since it is published on this site):

    Just my opinion

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    #194797

    Lehigh
    Participant

    Mike, sounds as if on the one hand you don’t believe any of this stuff can be learned. It also sounds like you don’t believe that processes with steps need to be documented or that methodologies need to consist of processes so don’t have to be documented. I also get the impression that unless people are lucky enough to be a magician like you or at least born a ‘natural’ dancer like your wife your fate is hopeless. Somehow your wife just got out of bed one morning and became an overnight dancing sensation w/o taking any lessons. Somehow without any help you became an Expert consultant overnight w/o any guidance. Bully for you!

    However for the rest of us mere mortals, I suggest that facilitating a workshop doesn’t come naturally; how to do it must be learned in some fashion, either from reading, rehearsing, observing others, etc. Unfortunately, for the rest of us creating a VSM, QFD or performing DOEs had to be learned.

    I suggest you try to remember back when you were younger and were acquiring these skills for the first time or struggling to learn how to facilitate a workshop better, or how to question a COO or CFO more thoroughly to better capture their issues so as to be able to organize them in some way that would make sense to them; or how to help them prioritize the symptoms of their organization’s sickness so that they could actually begin to address the real problems getting in the way of their company’s success and admit how un-Expert-like your approach seemed then.

    To suggest that you or anyone else can perform such feats out of the box w/o any guidance from others at some point in your development is ludicrous. I suggest that you like everyone else needed instruction at some point required that you read something, observe someone doing it followed by you doing it with some guidance given.

    One person who took part in this discussion had asked for more information so I gave it to him and as a courtesy offered it to others. I think that anyone who writes articles, offers up a topic for discussion or answers a topic is self-promoting. If you believe that there is something wrong with this I suggest that you don’t publish anything, participate in any discussion or offer your opinions about anything as you will be committing the sin of self-promotion.

    But then you also refer to your own accomplishments and isixsigma byline. Now I am confused. As I review your articles, I note that at least one of your publications discusses a Plan: “A Plan for a Five-day Kaizen” by one Mike Carnell. You also refer to some common tools and techniques for planning Kaizen event. In another article you discuss “what a Kaizen event is and address how to run successful events”. For another article you mention that “[Six Sigma] is a collection of tools. It is a methodology. It is a thought process that dissects the large picture into smaller parts and reassembles it into a more efficient configuration”. So it seems to me that at least at one time you thought that what you were doing was transferable and useful for others. I particularly liked your piece entitled, “Ask the Expert: Six Sigma – The Way We Work” where you answer some teed up questions about Jack Welch and GE work processes, critical factors in changing business processes so that Six Sigma becomes part of an organization’s DNA. Sounds to me like self-promotion.

    Because of your hubris you missed one of the major points of this whole discussion. Let me simplify so even you can understand. One must crawl before they can walk, walk before they can run, run before they can learn to play basketball, learn to play basketball before they go pro. Without a good foundation there is no becoming a great dancer, no becoming a good facilitator, no becoming a pro basketball player and so on and so on.

    Just my opinion.

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    #194798

    Mike Carnell
    Participant

    @Kelehigh You took some big jumps in there. At no point did I ever say things were not transferable. I have been in the middle of training belts since the Allied Signal deployment. At no point have I nor anyone working with me ever portrayed ourselves to anyone as being so enlightened that we could produce a “Recipe” and if you follow our recipe (which requires little to no thought) that you will then have a thinking process.

    As far as the self promotion, I have a few posts on this DF and at no point have I ever asked a question so I could come back later in the string and announce that I had discovered something and it is XYZ. That is blatant self promotion.

    The “Ask the Expert” article was done by iSixSigma. By definition it cannot be self promotion.

    Just my opinon

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    #194799

    Chris Seider
    Participant

    My colleague and mentor is saying there is no way to teach how to solve a problem with a flow sheet or it would be so ridiculous with all the twists and turns of decision trees. However, the basic methodology of DMAIC can be taught. Many of us advocate to our clients a training environment WITH projects to apply the learnings using an adult learning model.

    No properly scoped problem will use all tools or statistical techniques. The skill is to know the plethora of tools and when to apply them.

    We all agree knowledge transfer is not a one time event.

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    #194800

    MBBinWI
    Participant

    @elaw – Eric: re-projects geared towards cost reductions. You are correct that many organizations get into LSS because they were sold on the quick cost reduction/payback of the methodology. Those that stay with that focus generally fizzle out quickly (mostly, I would say, because the cost reductions are really mostly low hanging fruit that are captured not from a good methodology/implementation, rather, because they finally focus some attention on this low hanging fruit. As soon as this is picked and the really hard work of true projects start, the effort becomes more than the mgmt is willing to invest and it fizzles out). Those organizations that succeed are able to overcome the short-term cost reduction mentality and apply the methodology to all their improvement efforts.

    @Mike-Carnell/@Kelehigh – Those who can only follow a cookie cutter process never amount to much – you need to be able to adapt and overcome (I’ve yet to have a project that fit a nice clean cookie cutter/textbook flow). You do need a general process methodology, otherwise all you’ll have is chaos. You also need to have sufficient experience and “intuition” (basically just good judgment tempered by experience) in order to “feel” the project flow. Neither Lean nor Six Sigma can be cranked out through the sausage grinder without adapting to the realities of the situation. Nor can they be totally without structure, as there is a sequence and a minimum of things that need to be done in order to be consistently successful.

    Just my humble opinion.

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    #194802

    Robert Butler
    Participant

    …so the Cliff Notes version of MBBinWI’s last post is that no plan of battle ever survives first contact with the enemy.

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    #194805

    Mike Carnell
    Participant

    @MBBinWI and @rbutler A famous/notorious Mike Tyson quote “Everyone has a plan – until they get punched in the face.” I agree whole heartedly with MBBinWI. When people do things the way Arthur Murray taught dancing they stop thinking and they stop feeling.

    John Evelyn from Trident Leverage Group has a great thing he does where he asks people if when they are driving down a road and they see a red octagonal shape coming up on the right side (in the US) of the road if the think – ok ease off the gas peddle, lift my right foot off the gas, move it to the left, start to apply pressure to the brake,……….,stop. No you are programed and you don’t think and you stop. That is what happens when you feed people a recipe.

    People who teach tools to Belts and do not tie it to why you are doing these things in Define, these things in measure, etc are teacing a recipe. You get projects that look bureaucratic. No thought just people executing tools. Conversely people who understand DMAIC and that the tools are simply there to support the thought proces understand things on an entirely different level. They understand why I need to test for equal variances before I run the t test – I need to undersand if I am going to check the box in Minitab about assuming equal variances and they undrstand that checking that box is the difference in between using a pooled std deviation and one that is not. They also understand the difference it makes in the analysis. Anyone can create a recipe for doing those steps but understanding why I do those steps and the difference it makes on what I need to know/understand to accomplish what I am doing in the Analyze Phase.

    The statement that here is a recipe that will lead you to a “thinking process” is delusional. It goes the other direction.

    Just my opinion.

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    #194806

    MBBinWI
    Participant

    @rbutler – Robert: No, the reality is that no plan survives first contact. As you may (or may not) know, I’m a former Army officer. One of the things that I learned is that planning was crucial, but not deterministic. You must have a well thought out plan with rational deviations from that basic plan to understand how the plan might vary. To not understand the options that might occur is at best wishful thinking, and at worst naivete.

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    #194809

    Robert Butler
    Participant

    …well, ok, I guess as far as Cliff notes brevity is concerned the words “battle” and “with the enemy” could be viewed as excess verbiage …. :-)

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    #194827

    Carlos Navarro
    Guest

    Hi all,

    Can send me information materials about TLS interation, I´m very interested in that combination. Thanks so much

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    #194831

    MBBinWI
    Participant

    @rbutler – that’s about right!

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    #194862

    Six Sigma is a problem solving methodology wrapped around the DMAIC process…. Lean does not have this process… TOC does not have this process.. they have random tool usage based on the experience ofthe problem solver..

    Lean Six Sigma was a compromise to embrace the Lean toolkit in the DMAIC methodology… Still the greatest problem solving system to date ! TOC a Tool kit

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    #194866

    Chris Seider
    Participant

    Some of us learned that lean tools were greatest in the Measure, Improve, and Control phases of DMAIC.

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    #194872

    MBBinWI
    Participant

    Ziggy: You’re wrong – TOC has a 5 step process.

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