Six Sigma is a quality management approach that seeks to minimize or eliminate defects or errors in products and business services. Originally developed to improve manufacturing processes, the tools and techniques used in Six Sigma are now considered industry-agnostic, which means they have been successfully used in such sectors as aeronautics, electronics, pharmaceuticals, retail and more.
The "sigma" part of Six Sigma refers to the data analysis portion of the process. Following Six Sigma techniques, a team gathers and analyzes data about product manufacture or service creation/delivery to determine the standard deviation (sigma) between the mean and the nearest customer specification limit. The goal is to limit defects or errors to a maximum of 3.4 per million opportunities. (In even more technical language, according to several Six Sigma sources, a "normally distributed process, with normal distribution variation about the mean, would need specification limits of +/- 6 sigma to produce less than 3.4 defects per million opportunities.")
Organizations that have adopted Six Sigma processes may also see improved customer service, shorter cycle times and better compliance with regulations and business development standardization. However, the rigors of Six Sigma make its processes somewhat difficult to implement, and it typically takes months or years before all relevant employees are on board, following the processes closely and consistently enough to realize such benefits and value.
Overview of Six Sigma certifications
Unlike most IT-related certifications, Six Sigma certs are available from several different certification bodies, such as the American Society of Quality (ASQ) and the International Association for Six Sigma Certification (IASSC). That means either the individual seeking certification or the individual's company must research and compare programs before committing to one in particular. Each certification body offers similar (not identical) Six Sigma certification levels, although the following are mostly standard across programs:
- Yellow Belt: This person is a project team member who supports project improvements.
- Green Belt: This person also support project improvements, helps with statistical analysis, and may lead projects in a part-time capacity.
- Black Belt: This person leads projects (usually full time) and often trains, coaches and/or supervises project members.
- Master Black Belt: This person develops project metrics and strategy, serves as an organization's go-to Six Sigma person, and trains and coaches Black Belts and Green Belts.
Unlike some IT certifications, Six Sigma certs do not form a certification ladder. That means a Yellow Belt is not a prerequisite to a Green Belt, you don't need a Green Belt to become a Black Belt, and so forth.
Job opportunities for Six Sigma certified professionals
Just as there isn't one industry to which Six Sigma processes apply, Six Sigma job roles vary. The most common roles are project manager, project or process engineer, and quality assurance engineer. However, because employees from many different departments may participate on a Six Sigma team, you can also find business intelligence analysts, operational risk managers, software developers and consultants, to name a few.
There's a healthy job market for Six Sigma certified professionals. Job websites such as Simply Hired and Indeed.com show more than 2,500 open positions for Six Sigma Green Belts and about 3,000 for Black Belts, but the numbers drop below 200 for Yellow Belt. Master Black Belts are mentioned in about 1,000 job postings each day.
On the salary front, data from Glassdoor and PayScale indicates that the U.S. average annual salary for a Yellow Belt is about $68,000 and a Green Belt is $72,000. A Black Belt can expect just under $90,000 (on average), whereas a Master Black Belt averages $119,000, but it's common to see job descriptions with salaries of $135,000 to $150,000, and sometimes more.
Becoming Six Sigma certified
To achieve a Six Sigma certification, a candidate should expect to meet experience requirements, pass a written certification exam and demonstrate hands-on competency. Most of the various certification bodies offer training (which is recommended but not typically required) as part of a certification package, which also includes training materials and written exam costs. Exams are administered by Pearson VUE, Prometric, or the certification bodies at special conferences and educational events.
Written exams are usually multiple choice and increase in allotted time and difficulty at each certification level. Where a Yellow Belt written exam may take 90 minutes, a Black Belt exam may take four hours. The hands-on portion of certification testing usually means completing one or more quality projects with signed affidavits. For example, a Green Belt might be required to complete one project, a Black Belt two projects, and a Master Black Belt 10 or more projects. Most certification bodies allow candidates to count college or university degrees toward the work experience requirements.
The American Society for Quality (ASQ) certification program has 18 certifications. It includes the Yellow Belt, Green Belt, Black Belt and Master Black Belt credentials, along with 14 others that are specific to job roles, such as Biomedical Auditor and Calibration Technician.
Candidates for ASQ certifications can save money by becoming a member, which costs $29 to $159 per year, depending on whether you join at the Student, Associate or Full level. The following table shows exam fees for a sampling of ASQ certifications.
ASQ Yellow Belt
ASQ Green Belt
ASQ Black Belt
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ASQ Master Black Belt*
$2,229 / $2,074
* A candidate for Master Black Belt must also pay $650 (or $495 for members) for a portfolio review.
IASSC focuses on Lean Six Sigma, which combines lean manufacturing processes and principles within the Six Sigma structure. IASSC exams are based on topics in the IASSC Universally Accepted Lean Six Sigma Body of Knowledge, or IBoK. Speaking of lean, the IASSC Lean Six Sigma certification program has only three (but reputable) certifications: Certified Yellow Belt, Certified Green Belt and Certified Black Belt.
IASSC stands out in the Six Sigma field because the organization does not offer training, and it does not require work experience or hands-on projects as part of its certification requirements. Candidates must simply pass a written exam.
The cost of IASSC certification exams are $395 for the Certified Black Belt, $295 for the Certified Green Belt and $195 for the Certified Yellow Belt.
Where else can you get Six Sigma certified?
The Council for Six Sigma Certification maintains the Six Sigma Body of Knowledge for Black Belts, Green Belts and Yellow Belts. It also accredits organizations to administer certifications. You can search the Accredited Six Sigma Provider Directory to locate certification bodies and training providers (which usually are one and the same).
You can also check out other organizations that offer Six Sigma training and certification, such as Six Sigma Certification Tulsa and Villanova University. And be sure to visit the iSixSigma website for all kinds of Six Sigma resources, such as training materials, a dictionary, project templates and examples, a blog, Six Sigma tools, and a job board.