What is Six Sigma?
Six Sigma (Six Sigma, or simply 6σ) is a powerful tool for the improvement of productive processes. It is based on the reduction, at ambitious but achievable levels, of the appearance of defects in products / services. The origin of its name comes from the normal statistical nature of the processes, in which σ is the standard deviation, the best indicator about the variability of them.
A process with very low levels of variability assures us that it is within the established limits, except in an almost negligible amount of opportunities. Achieving 6σ is equivalent to a 99.99996% efficiency or, what is the same, to a maximum of 3.4 defects per million produced (3.4 DPMO).
It is a completely customer-oriented methodology, which is based on other previous improvement techniques among which are the Total Quality Systems (TQM), the Statistical Process Control (SPC), the PDCA cycle of Deming, and Lean Manufacturing. Given their similarity in some aspects with Lean, they can complement each other harmonically and synergistically, which gives rise to a methodology that is currently widely used and diffused, called Lean Six Sigma (LSS).
Like many of these quality tools, Six Sigma emerged in the field of the manufacturing industry although, in recent years, it has been expanding to service companies with undeniable success.
Six Sigma requires a very high degree of commitment from affected personnel, whose members must be involved full time in the improvement projects. Those who participate in the program must receive special training, which is usually dictated by black belts (described below). True leaders are the ones who must carry out the program, promoting the principles of Six Sigma to the entire organization and stimulating the active participation of the staff in the continuous improvement. This leadership must always be from top to bottom, with a high degree of commitment and support from Senior Management. Understanding the client’s needs in an open and in-depth manner is one of the fundamental principles of the methodology. This allows you to understand how processes currently work and what can be improved.
It is clear that implementing Six Sigma requires hard work, with excellent long-term results, but with very significant intermediate improvements. The data is very important for the statistical analysis of the processes. The way to obtain, analyze and treat them is another of the secrets to the success of the program. The two natural consequences of implementing Six Sigma form an ideal combination: cost reduction and increased sales.
The 5 stages of the Six Sigma implementation process
The implementation of Six Sigma is carried out through five well-defined steps, known as the DMAIC cycle (Define, Measure, Analyze, Improve and Control / Define, Measure, Analyze, Improve and Control).
First you must define the objective of the program, the problem to analyze and who will participate. Then measure the current state of the problem in question, the amount of current defects. The next step is to analyze the causes of the problem, then improve the process through the minimum possible investment. Finally, the improvement system implemented over time must be controlled. These five steps will be treated in another publication.
Who is who in Six Sigma?
Six Sigma requires a certain human structure. This structure is formed by:
Yellow Belts: are people who participate part-time in Six Sigma programs and are involved in problems belonging only to their usual area of action.
Green Belts: are experts with full-time dedication in Six Sigma programs. They usually have certifications that endorse them, which allows them to lead projects.
Black Belts: They are certified leaders who massively disseminate the culture of improvement proposed by the method. They have a systemic vision of the organization and can implement Six Sigma at all levels. They also advise and train Green and Yellow Belts.
Master Black Belts: are people with great previous experience as Black Belt. They direct projects and train Black Belts. They do not always exist as a figure.
There are also the Champions, who are responsible for the area, who provide the necessary resources and facilities for the correct implementation of the program.