What is the definition of Six Sigma?

Six Sigma is more than a clever name or even a business analysis tool. It has been best described as “a comprehensive approach to dramatically improving the quality and consistency of products and services.”

As most of us are aware, sigma is one of the letters of the Greek alphabet.

In scientific and mathematical communities “sigma” is frequently used as a representation for standard deviation. Standard deviation is defined as the distribution around the mean (average) of a process or procedure.  If the distribution around the average (mean) is large, then there may be room to eliminate variability and tighten the distribution or spread, thereby improving overall performance.

In the world of Six Sigma, the term “sigma” is used to indicate how well a process is performing.  Higher sigma values represent better performance.  Sigma measures the capability of the process to perform work that is free from defects.  And a defect is any outcome that results in a dissatisfied customer.  It applies to services as well as products.

How Does Six Sigma Achieve its Quality Results?

By analyzing and identifying where and why failures occur in a process or system, it is possible to improve performance by incrementally eliminating the variability that leads to process failures.

When evaluating performance it is useful to consider what an acceptable failure rate would look like. On the surface a 95% success rate seems very high. A 99% success rate seems unthinkably high. But to put failure rates in perspective, consider the following items which each represent a 99% success rate.

Operating consistently at a 99% performance would yield the following results in these particular categories of measurement:

*        20,000 lost articles of mail per hour

*         Unsafe drinking water almost 15 minute each day

*         5,000 incorrect surgical operations per week

*         2 short or long landings at most major airport each day

*         200,000 wrong drug prescriptions each year

*         No electricity for almost 7 hours each month

What is the Value of Six Sigma to an Organization?

Six Sigma is primarily concerned with identifying, measuring and correcting defects per unit of production – whether it be services, products, lines of code produced, or any other activity, process, or procedure.  The term sigma refers to the likelihood that a defect will occur in a given process or procedure.  A higher sigma value signifies that there is less likelihood the process being evaluated will produce defects.  As failures and defects are identified, measured, and corrected, the following benefits are likely to accrue to the organization implementing these improvements:

·         Production costs will decline

·         Quality control costs will decrease

·         Cycle times and will improve

·         Throughput will increase

·         Customer satisfaction will escalate

In summary, there is much to recommend about Six Sigma - when it is properly incorporated and executed within an organization.  However, Six Sigma requires patience, focus, dedication, and a healthy level of commitment throughout the organization. By its nature, it moves employees and organizations out of their traditional comfort zones. Over time, however, the benefits of Six Sigma can be profound.  It can make the difference in an organizations ability to survive and compete in an increasingly competitive global environment.