What is Six Sigma?

Six Sigma Defined
There are many definitions of Six Sigma out there, but in its most basic terms, Six Sigma is a way to improve processes with the ultimate goal of eliminating defects and improving quality. A manufacturing process is anything that contributes to producing final product. A machine, for example, is considered a process. Businesses processes can also be improved with Six Sigma, with the goal of increasing efficiency and eliminating mistakes.

History
Six Sigma gets its name from the bell curve used in statistics. The capability of a process (its ability to produce products within control limits or specifications) is represented as a bell curve. A "Sigma" is one standard deviation away from the mean. When a process exhibits six sigmas (three above the mean and three below) then the defect rate is extremely low-- almost at zero. But you don't need to understand the statistics of Six Sigma to understand how it works. Just remember that Six Sigma involves measuring a process' capability using statistics. Let your company's statisticians and "black belts" worry about the math (more on black belts later).

Six Sigma was first used at General Electric (GE) in their manufacturing operations to improve product quality, reduce waste, and ultimately save money. Due to GE's success with Six Sigma, other manufacturers starting implementing Six Sigma programs. Today, companies across all industries are using Six Sigma to improve processes. Even financial services firms are implementing Six Sigma for their billing and accounting processes.

Methodology
Six Sigma is carried out through the DMAIC cycle: Define, Measure, Analyze, Improve, Control. These five steps are repeated over and over again until the process has reached Six Sigma in terms of its capability and defect rate.

In the Define stage, the problem is defined in very specific terms. The problem is what, exactly, needs to be improved upon. Although this might seem simple, identifying or diagnosing the specific issue within a certain problem can be challenging. The root cause isn't always apparent. Additionally, if the problem is not clearly defined, then there is no way to measure if it has improved.

In the Measure stage, various types of data is collected. In manufacturing, this data could be the measurements of a specific product-- its height, weight, diameter, or other attributes. Having accurate, reliable data is extremely important. Data should be collected from multiple samples so that there is enough information for statistical validity.

During the Analyze stage, scientific, statistical analysis is used to interpret the data. This analysis is presented in the form of statistical charts and graphs. Businesses usually employ software to create these graphs, so they don't have to manually create them. Statistical Process Control software is commonly used in manufacturing to analyze data in various formats.

Once the data has been charted and analyzed, it's time to make improvements based upon the findings in the Improve stage. The improvement could be a simple fix, or something that is more complex, costing additional time and money. However, the ultimate savings in time and money yield a return on the investment of improvement tools.

In the Control stage, the new improvements are incorporated into the "controls"-- the way a business ensures that it's meeting certain requirements.

After the control stage, the cycle repeats to re-define the problem (or make it more specific) measure it, analyze it, improve it and control it.

Six Sigma Certification
There are various levels of Six Sigma certification. Similar to Karate, the colored belt system is used, but without so many colors. A White Belt is the first level of certification, followed by the Green Belt, the Black Belt, and then the Master Black Belt. To become certified, it's necessary to attend training and pass a certification exam. Six Sigma Black Belts and Master Black Belts are in high demand, and businesses look to these experts to lead the company's Six Sigma initiatives.

Is Six Sigma Here To Stay?
Many business experts are speculating if Six Sigma is here to stay, or if it's just the latest trend. It's been around for years, but its adoption has dramatically increased within the last five years. The market for Six Sigma is still rapidly increasing, with more and more companies investing in software for Six Sigma and employees with the Six Sigma certifications.

To summarize, all you really need to know about Six Sigma (if it's not part of your job) is that it helps improve quality and eliminate defects, with the potential to save companies a significant amount of money.