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Lean and Six Sigma, two popular process improvement methods, work together as Lean Six Sigma to help people and organizations achieve their goals of making customers happy, engaging workforces, reducing errors and costs, and much more.

Here are the differences between them and the benefits when they’re combined.

Infographic: Lean - or - Six Sigma? -

Do you have a favorite soup? Do you like a Lean Gumbo? Or do you prefer a Six Sigma Stew? The strength of your efforts depends upon what goes in the bowl. Why limit yourself? Let the situation serve up the soup. Use all your options – Lean and Six Sigma – to achieve your goals and ensure your success.


Six Sigma

  • DMAIC – A five-step process improvement method (Define, Measure, Analyze, Improve, Control)
  • Project Charter – A one-page document that lays out the process problem, goal, scope, timeline and basic outline of an improvement project
  • Data Collection Plan – A guide to what data will be collected, by whom, how and when
  • Basic Statistics – Measures of the average, median, range and standard deviation of any data set
  • Histogram – A Graph that provides a snapshot of a data set displaying the spread, shape, average and range of the data
  • Pareto Chart – A cascading Bar Chart that displays the sources of process issues from the biggest source to the smallest
  • Measurement Systems Analysis – A way to test the accuracy, repeatability, reproducibility and precision of data collection
  • Hypothesis Testing – A way to provide statistical rigor to theories about the root causes of process issues
  • Design of Experiments – Controlled tests to assess the effectiveness of different ways to run a process with the goal of picking the best conditions, materials and methods
  • Statistical Process Control – Monitoring a process to ensure that it consistently meets customer requirements
  • Control Chart – A powerful time plot used in statistical process control signals the presence of special cause variation in a process

It doesn’t matter where the tool comes from – what matters is solving the problem!

Lean + Six Sigma Common Benefits

Stronger Customer Focus

  • “Live in a constant state of awesomeness!” – Kimberly Fleming

Engaged Workforce

  • “Customers will never love a company unless employees love it first.” – Simon Sinek

Problems Solved at the Root

  • “Why is it that we never have enough time to do it right the first time, but we always have enough time to do it over?” – Jack Bergman

Error Reduction

  • “The only real mistake is one from which you learn nothing.” – Henry Ford

Increased Capacity

  • “The future depends on what we do in the present.” – Mahatma Gandhi

Greater Efficiency

  • “Efficiency is doing better what is already being done.” – Peter Drucker

Minimized Costs

  • “Creativity before cash!” – Mike Osterling

Maximized Profits

  • “Profit in business comes from repeat customers. Customers that boast about your product or service and bring friends with them.” – W. Edwards Deming

Operational Excellence

  • “We are what we repeatedly do. Excellence, then, is not an act, but a habit.” – Aristotle

Lean and Six Sigma are two great toolkits and together they provide all the support you need to delight customers, reduce costs and build strong teams. Embrace the power of “Yes, and” instead of “Either or” – life is richer with options!

This Post Has 13 Comments

  1. Yikes. By removing wastes aren’t you inherently reducing variation and improving stability? Did I miss something along the way? Doesn’t the PDSA structured problem solving approach get you to the same place as DMAIC? Aren’t the daily management systems and visual management systems a form a data collection?

    1. That’s right @danfeliciano:disqus – Lean and Six Sigma have some classic differences but as you describe, they have more in common than not. Six Sigma is known for reducing defects to 3.5 per million opportunities and one of the 8 Wastes is Defects. That’s why we love the combo “Soup!”

  2. Great summary. Congratulations. Yes, the “either/or” is mistaken. It must be “and”.

    However, the resulting “Operational Excellence” with the implicit excellence by repetition is valid for many businesses but leads to the mistaken idea that either non repetitive businesses are wrong or that they cannot apply Lean and Six Sigma.

    Incorporating the “Discipline of Market Leaders” and understanding that both Lean and Six Sigma can be applied to businesses that are driven by customer intimacy or by product leadership would be a good improvement.

    Lean IS NOT the Toyota model, for more that Lean may owe to Toyota. Lean is the least waste execution of the strategy of a given business and, therefore, the specifics of Lean for that business are subordinated to the strategy. A business that chooses customer intimacy as the basic strategy will apply Lean in a very, very different way than Toyota. And Six Sigma in a very different way than GE.

    To define Lean and SixSigma based on how their advertisement companies did them is an unnecessary narrowing of those instruments.

    1. Thanks @disqus_mMHq7rUlEG:disqus – as Jim Collins would say, we agree on the tyranny of the “or” and embrace the genius of the “and.” It’s interesting to hear your thoughts around reinforcing the idea that Lean Six Sigma can be used by organizations embracing either Customer Intimacy or Product Leadership and not just Operational Excellence. I would agree since regardless of the value discipline, organizations still need to meet industry standards across the board. As for the definition of each of the improvement methods – we include the founding organizations of both Lean and Six Sigma to provide a sense of history but clearly, by combining Lean with Six Sigma we have moved past how each was defined by either Toyota or Motorola. Regardless of the strategic direction, the evolution of process improvement continues. Thanks again for taking the time to provide your thoughts!

  3. Just like getting fit. Do we need to eat less, or exercise more? The answer is most often, “Yes!”
    Some days require more of one effort versus the other, but in the long run both are needed.

    Some days waste is staring me in the face and tripping me in the office, so a quick Lean approach is needed. Other days we are frustrated by lingering problems that require some sophisticated study and analysis to resolve, so we take out our Six Sigma tool box.

    Learning both realms helps dramatically in allowing us to use what ever blend is needed.

  4. I thought TPS/Lean added the six-sigma tool set to TPS/Lean in the 1990’s? Lean/TPS is about culture first. Within their culture of continuous improvement, six sigma has been assimilated. I’m always perplexed by the static reviews of TPS from the 1980s.

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