Lean Six Sigma and Operations Research

Continuing the discussion of Operations Research and Lean Six Sigma, I would characterize the difference as a matter of marketing and emphasis. In full disclosure I should state up front what must be obvious to anyone reading this blog that I’m a certified operations research analyst. According to some who know me that is probably not the only area where I can be described as certifiable, but that is another topic altogether!

For some, my academic background in OR might suggest a bias and I accept the possibility as it would otherwise be unprofessional. However, as someone who claims to be data driven, I hope to convince you that my assessment results from fair and open-minded research.

I searched on the web to find some practical explanations of both LSS and OR and offer the following as an introduction to the rest of the blog.

The search for something humorous related to operations research proved totally fruitless. So, there’s a big different, at least the world has developed a sense of humor about LSS. Operations Research on the other hand hasn’t been spoofed as yet, at least not that I could find. It was a bit interesting though that the search did find a fantastic video of a bone marrow extraction!


One place to start looking for a valid comparison is with the body of knowledge that is comprises the essential skill sets in LSS and OR. The American Society for Quality’s Body of Knowledge for Black Belts requires expertise in business process management, change management, project management as well as the fundamentals of Define, Measure, Analyze, Improve and Control (DMAIC). More recently, there has also been an emphasis on Design for Six Sigma – for more on that specific topic I suggest you look up a book my Mark Kiemele and his associates at Air Academy Associates, Design for Six Sigma: A Tool Guide for Practitioners. Certainly, the other major skill requirement for an effective Lean Six Sigma professional is a thorough understanding of experimental design, data collection, survey techniques and statistics.

I’ve provided estimates of time and practical projects for becoming LSS certified below. The data come from a research report entitled “Six Sigma Certification Research Report” (https://store.isixsigma.com/product/six-sigma-certification-research-report) The report compared the requirements from three different companies.

Minimum number of projects completed as a leader

Level Motorola DuPont Microsoft
Green Belt 1 1 1
Black Belt 2 2 Must be GB certified + lead one project
Master Black Belt 12 (lead or mentor) BB certified plus trainer certified BB certified and lead “cluster” of related projects

Days of Training

  • Green Belt: varies, but on average 9 days
  • Black Belt: also varies, but on average 20 days beyond Green Belt.
  • Master Black Belt, no surprise – also varies, but on average 10 days beyond Black Belt.

Time in Role

  • Black Belt:  18-24 months
  • Master Black Belt:  Black Belt + 12 months

Type of Exam

  • Green Belt:  Written
  • Black Belt: Written and Oral
  • Master Black Belt: Written and Oral plus confirmation by champion

In contrast, a typical undergraduate degree in operations research requires courses in:

  • calculus ( ~3 semester classes), probability and statistics (~ 3 classes),
  • linear algebra (~ 1 class),
  • differential equations (~1 class), advanced analysis (~ 1 class),
  • discreet mathematics (~1 class),
  • abstract algebra (~1 class),
  • computer science & programming (~2 -4 classes),
  • physics (~2 classes),
  • chemistry(~ 2 classes),
  • behavioral science(~2 classes),
  • industrial engineering (~3 classes),
  • Operations Research (~6-8 classes),
  • General electives (~9-10 classes),
  • technical electives (~3-4 classes),
  • physical education (~2 classes),
  • writing seminars(~2 classes).

Students are also required to participate in student seminars and teams who get practical experience working with real clients through the department. A master’s program will add an additional 6-8 technical classes as well as financial accounting classes. The Ph.D. program generally requires another 20 – 45 credit hours beyond the master’s program depending on the university. As an example, I’ve copied the requirements from North Carolina State below.

  • Ph.D. students must satisfy the course requirements for the MSc Degree in Operations Research.
    A minimum of 72 credit hours is required to receive a doctoral degree. Students who received their MSc Degree from NC State can transfer up to 36 credit hours towards their PhD program.
  • Students who received their MSc Degree from a university other than NC State may transfer up to 18 credit hours towards their PhD program.
    The qualifying examination is intended as a “screening” mechanism to verify students’ potential for pursuing high quality independent research at the early stage of their graduate studies.
  • Linear (OR505), Nonlinear (OR706) and Stochastics (ST/MA546 & ST/MA746, or ISE760) examinations
  • Dynamic Programming (OR709) and Dynamical Systems (OR/MA 531) examinations
    • Participating Department Qualifying Examination
      The OR PhD qualifying exam consists of two parts. Part I consists of three distinct written examinations in the areas of Linear Programming, Nonlinear Programming and Stochastics (LNS).
    • or Part II, a student may choose a Participating Department Qualifying Exam (see below) or the DPDS.
    • Part I and Part II MAY both be taken at the same time. They MUST both be taken within a one-year time period.
      In addition exam questions are provided by other “participating departments” prior to PhD research approval. Participating Department Qualifying Exams
    • Mathematics – Choose one of the following sequences:
      o Numerical Analysis MA 580 and MA 780
      o Applied Matrix Theory MA523 and MA723
      o Analysis MA515 and MA715
      o Ordinary Differential Equations MA532 and MA732
      o Partial Differential Equation MA534 and MA734
      o OR students may NOT use the probability option of the Mathematics Qualifying Exam as a PDQE.
    • Industrial and Systems Engineering – Select two of the following areas:
      o Manufacturing Systems
      o Production Systems
      o Ergonomics
    • Computer Science – Select one of the following areas:
      o Computer Organization and Architecture
      o Foundations of Computing
      o System Software
    • Statistics – Pass departmental Basic Examination at Masters Level
      o ST501 – ST701, ST741 – ST742, ST743.
    • Economics – Choose one of the following sequences:
      o Micro Theory ECG701 and ECG702
      o Macro Theory ECG704 and ECG705

I claim that the OR program from most academic institutions is significantly more diverse in the range of skills the practitioner must survey.  To be fair, the LSS practitioner in an organization has the advantage of far more detailed understanding of the organization’s culture and operations.  I would claim that this advantage saves months of dialog and research when compared with the learning curve most likely required by an operations research analyst who  comes from outside of the organization as a consultant.

Lean Six Sigma has benefitted from a strong marketing program as the result of its successes at Motorola, GE, Bank of America and a host of other companies that decided to take a data driven approach to change management.   Operations Research Analysts should probably have taken one or two business classes, perhaps emphasizing marketing and advertising,  Then perhaps they could have avoided meaningless slogans such as “The Science of Better!”

So to wrap this up, whereas Operations Research may provide more in-depth knowledge and background for the ‘technical’ toolset available for process improvement, LSS has the advantage of a clear business focus with significantly reduced up-front learning curve.  On the other hand, presuming the OR analyst is engaged after earning the credentials, the cost to a company is significantly reduced when compared with building a LSS capability from scratch in house.

With all that having been said, er rather written, please let us know if we can help you with your bottom line!

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