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What Is Six Sigma in Operations Management?

Sid Kemp is a business consultant and author of 10 books on project management and business success.

Six Sigma was designed for high-end engineering and manufacturing and is at its best in high-stakes situations. But it works for all companies—even those in service industries.

Six Sigma was designed for high-end engineering and manufacturing and is at its best in high-stakes situations. But it works for all companies—even those in service industries.

What Is Six Sigma?

Six Sigma is a great method with a lousy name. It started as an obscure statistical concept and has since been elevated to a corporate goal by Jack Welch of GE. Unfortunately, it is also an industry buzzword, and most people are confused about what it is, what it means, and what it is good for.

Six Sigma is a methodology for improving the quality of operations management by eliminating errors and defects, reducing costs, and saving time. It is primarily intended for high-end engineering and manufacturing, where companies seek "six sigma" quality (fewer than seven defects per million), but it can be adapted for other product and service industries. It is expensive to implement, but it's worth it; done properly, it pays for itself and makes companies into industry leaders and Centers of Excellence.

What Six Sigma Is Not

Six Sigma is a valuable tool for any industry, but there are many misconceptions about what it can do. Here are some of the more common unrealistic expectations businesses may have about this methodology.

  • A quick fix: Initial investment is likely to be costly. After that (perhaps within the year), there will be a big return.
  • A magic pill: Everyone wants one-size-fits-all solutions. DMAIC isn't like that. It is more like going to a medical specialist for a whole series of tests. Then there will be surgery and rehabilitation. But, when it's over, your company will be like the Six Million Dollar Man: Better, Stronger, Faster.
  • A quick romance: Remember, your competitors can implement Six Sigma, too! You can't implement it just once and expect to remain an industry leader.
  • The ultimate solution: Markets, customers, and the economy will keep changing. Six Sigma is part of the best way to face these changes and remain an industry leader. But that will only happen if everyone at your company adopts Six Sigma thinking and applies it to every problem: New ones that come up and old ones that come back to haunt us.

Six Sigma Principles for Operations Improvement

There is no Six Sigma standard method, but if you read a lot of texts, you'll find all of these essential principles:

  • Senior executive support. Six Sigma will only work if the quality engineers and department managers are supported by senior executives. Note that this is different from classical quality management, where executive leadership is required. And it may be a crucial difference. Sometimes, support from executives is not enough, and Six Sigma initiatives fail due to a lack of executive leadership.
  • Top-down training. Six Sigma may use outside expert consultants, but it can't rely on them for long. Everyone in the company, division, or department must receive Six Sigma training. Executives and senior managers must understand its business value and how to support it. Non-technical managers must know how to work with it. Engineers must know how to do it. And workers must know how to communicate issues with the engineers.
  • Include the voice of the customer. Ultimately, there is only one measure of success: Happy customers who buy our stuff and come back for more. So, let's start there: The customer defines what quality is in our products and services through focus groups, surveys, complaints, and other tools we use to listen to our customers.
  • Create an infrastructure to support success. Six Sigma is not a one-time fix. To maintain high-quality production, the whole organization must be able to communicate about errors and defects and how to eliminate them.
  • Develop short-term projects with specific goals. Rather than trying to run around and fix everything all at once, we organize Six Sigma initiatives into specific projects. Each project has a clear goal, and whichever projects benefit the bottom line most get done first.
  • Focus on process improvement. An essential element of all quality management is to prevent, detect, and reduce errors in the process to reduce defects in the product.
  • Clear and consistent methodology. Across companies, there are many ways to do Six Sigma. Within one company, there must be one clear, overall approach adapted to each area of the business.
  • Focus on people and processes. Focusing on quarterly profits or defective products will not improve profits or reduce defects. Excellent processes performed by trained, motivated team members produce high-quality products and high profits.

Operating according to these principles, Six Sigma companies improve operations and quality with many specific tools.

Six Sigma Tools

The Six Sigma toolkit is chock-full: a typical text lists over 50 different tools that can be used to solve management, operations, and quality problems. Some are common sense, some are simple logic, and some use very advanced statistics. It is the job of Six Sigma Black Belts and Green Belts to pick the right tool for each job.

The most central tool is DMAIC, which stands for Define, Measure, Analyze, Improve, and Control. DMAIC is both the methodology that governs the entire Six Sigma management system and also the method that creates the steps for each project. In brief, we think diagnostically. We:

  • Define the customer requirements or executive directives that are to be met.
  • Measure what is happening now. What needs to change from where we are now to meet the goals we defined?
  • Analyze the root causes of the problem, so we know what changes we can make to meet our goals.
  • Improve the process so that it achieves the goals.
  • Control the process so that, going forward, the goal is always achieved.

Some Six Sigma tools are common sense methods. For instance, the Spaghetti Diagram is a floor plan that shows how things move back and forth through manufacturing from one department to another. If the diagram looks like a pile of spaghetti, then a lot of time and money is being wasted on moving stuff around, delays, and confusion. We can handle this by redesigning the factory and streamlining the process.

Many Six Sigma tools are borrowed from other methodologies. The Work Breakdown Structure (WBS) is a basic project management tool. Lean Methodology comes from Just-In-Time (JIT) manufacturing. Flow charts come from chemical engineering and data processing. The Five S system comes from Japanese continuous improvement (kaizen). The Six Sigma rule is: If a tool works, use it!

Many Six Sigma tools are statistical. Some, such as histograms and Pareto diagrams, don't require a statistician. Others, like ANOVA and the Nonparametric Test on the Equality of Means, should only be used by statisticians. (Anyone else would drop their spaghetti!)

Six Sigma training is an in-depth study of these tools and how to use them. Green Belt training focuses on using the tools to support projects. Black Belt training focuses on managing the projects to success.

Proper training in the Six Sigma methodology takes time and patience—but if you do it right, this toolkit can carry your business to the top of your industry.

Proper training in the Six Sigma methodology takes time and patience—but if you do it right, this toolkit can carry your business to the top of your industry.

Keys to Six Sigma Success

Six Sigma initiatives can keep companies from going bankrupt in these difficult times. They can also take a company to the top of its industry, making it an industry leader, a great place to work, a top competitor, and a Center of Excellence.

They can also fail miserably, wasting tons of money, creating conflict, and leaving things worse than where they were when the initiative was started. To understand why, read Business Success: Maturity & Capability or Negative Synergy. The ideas there apply to Six Sigma as well as to the Capability Maturity Model (CMM).

These four elements, though, are the keys to making Six Sigma Successes and preventing operational disasters:

  • Executive leadership. Six Sigma says that only executive support is needed. But experience shows that complete commitment on the executive level with leadership by example is essential to long-term success.
  • Standard methodology. Six Sigma will only work if everyone is trained and actually uses the parts of Six Sigma that apply to their work. All too often, people give lip service to the methods and go off and do their own thing. Then problems persist - and put a big drain on the bottom line - until the next initiative.
  • Projects. Six Sigma can't be implemented everywhere at once or in a mishmash, here and there. It must be implemented in a series of projects, addressing the biggest improvements first, and moving forward from there.
  • Keep measuring, managing, and improving. Corporate and team commitment to success must be supported by management controls and communications that measure results and ensure ongoing success.

Working like this, you can implement Six Sigma without creating a disaster. You'll stay in business and stay ahead of the competition. You may just find that your job and workplace are a great places to be, as well!

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


Sid Kemp (author) from Boca Raton, Florida (near Miami and Palm Beach) on May 22, 2013:

Hi Mel! Thanks for sharing your experience. A sad story, but the postal service is not alone, nor has it always been that bad. When Al Gore was Vice-President, he led a very successful effort to revamp the post office. (Who knows, Six Sigma at the PO may have started then, or grown out of it.) And some of the most frustrating work environments I've found are those that, at one time, were tops in quality management, and then it became a mantra. There was a factory near Pittsburgh, co-owned by Sony and Corning Glass, that made TV tubes. I went there as a trainer, and saw they had this problem in spades. Much of the world has gone this way, I'm afraid.

Mel Carriere from Snowbound and down in Northern Colorado on May 22, 2013:

The Postal Service, where I served a brief tenure in management, uses the words "Six Sigma" like a mantra that, if repeated enough, will fix everything. There are posters about it everywhere. Of course, I don't think it ever gets out of the "buzz word" stage because you see the results. Basically the postal service spent a lot of money supposedly implementing the Six Sigma program but they continue to use their same old, tired, uninspired business practices.

Sid Kemp (author) from Boca Raton, Florida (near Miami and Palm Beach) on September 16, 2012:

Thanks, PH! It's wonderful to hear of personal connections to concepts like quality assurance.

Theresa Ast from Atlanta, Georgia on September 16, 2012:

Fascinating Sid -- One of my sons was with IBM for five years in a "Quality Assurance" division. I was never sure exactly what he did or how IBM''s process improved things. Just as he was leaving IBM about ten years ago, I started hearing mention of Six Sigma, but I never understood what it was or how it worked. Thank you for making this both interesting and understandable. Voting +++ and Sharing.