Origins of Six Sigma
As part of our description of Lean Sigma or Lean Six Sigma, lets look at the origins of the term Six Sigma and Lean. Six Sigma is the brain child of Bill Smith, a Motorola Engineer and Vice President in the late 1980s and early 1990s. Bill Smith is the “Father of 6 Sigma”. During his tenure with Motorola, his Six Sigma improvement program generated billions in savings and improved profitability.
What is Six Sigma?
So what is Six Sigma and how does it relate to everyday work? Sigma is a statistical term, a unit of measurement that describes the distribution about the mean of any process or procedure. A process or procedure that can achieve plus or minus six sigma capability can be expected to have a defect rate of no more than a few parts per million. In statistical terms, only 3.4 parts per million are defective, a level that is very close to zero defects.
The term Six Sigma is used in three ways:
- A statistical concept implying virtually zero defects
- A term referring to methods and tools used to achieve six sigma quality
- An organisational structure defining roles and responsibilities
Achieving Six Sigma
The key goal of six sigma is virtually zero defects and this target is applicable to all areas of work. Achieving six sigma begins by identifying your product or service and your customer needs. Everybody makes a contribution to the business, whether it is on a production line, in a human resource department or operating a telephone.
Six Sigma starts by understanding:
- Our contribution to the business
- What is the product or service we provide
- Who are our suppliers and customers
Suppliers provide us with the ingredients and tools needed to carry out our work. Customers use the service or product we provide. It is very important to understand the critical requirements of customers. You need to know what are your customer’s expectations, both implicit and explicit as well as safety and regulatory requirements. These are the metrics that determine customer satisfaction and need to be managed.
Six Sigma as an Improvement Methodology
Six Sigma is more than just a statistical measurement; it also refers to an improvement methodology. The most common six sigma improvement methodology is called DMAIC which stands for define, measure, analyze, improve, control.
Define: Define the targets for the improvement activity.
Measure: Measure the performance of the existing system.
Analyze: Analyze the system to identify ways to eliminate the gap between the current
performance of the system and the desired goal.
Improve: Improve the system. Generate new ways of doing things better.
Control: Control the new system. Institutionalize the improved system.
Companies have different interpretations on how DMAIC is implemented. Some companies don't use terms like DMAIC but the core concepts can still be found in their internal improvement methodologies. As companies define critical customer metrics, measure current performance, analyze improvement opportunities, make improvements and control performance, the level of customer satisfaction improves and the company becomes more effective.
Continuous Improvement
Six sigma also refers to an organisational structure geared towards continuous improvement. Six sigma borrows terminology from martial arts ranking to define a hierarchy of training and responsibility levels.
Six Sigma classifies people's ability into four different rankings:
- Yellow Belt
- Green Belt
- Black Belt
- Master Black Belt
Master Black Belts are very familiar with statistical tools and management of six sigma projects. They act as in-house coaches on Six Sigma and assist in identifing potential six sigma projects. They devote 100% of their time to Six sigma and assist people with the ranking of Black Belt and Green Belt. Apart from being a statistical expert, they help to ensure a consistent implementation of six sigma practices throughout the organisation.
Black Belts operate under Master Black Belts and apply the Six Sigma methodology to specific projects. They are expert in the use of statistical tools. They devote 100% of their time to Six Sigma projects. Their primary focus is on six sigma project implementation.
Green Belts receive training in many statistical techniques but are not 100% dedicated to six sigma. Green belts are employees who take up Six Sigma implementation along with their other job responsibilities.
Yellow Belts are employees who take part in six sigma projects and will have received basic training in six sigma methodologies. Typically, yellow belt employees are very knowledgeable about the area being improved. They make a big contribution to improvement teams but do not lead projects on their own.
Six Sigma and Lean Manufacturing
The Six Sigma methodology is open to the use of a broad range of improvement tools. Tools used by lean manufacturing people are particularly useful and have gained widespread acceptance. Lean manufacturing is an improvement effort that focuses on eliminating waste in the value stream by reducing cost, generating capital, increasing sales and maintaining competitiveness. The value stream refers to the activities within the supply chain that are required to design and provide a specific product or value. The aspirations of lean manufacturing fit well with customer expectations in service industries as well as manufacturing.
Lean manufacturing originated in Japan after World War II. Japanese manufacturers were faced with shortages of material, finance and human resources. In order to maximise output from scarce resources, early Japanese leaders such as Shigeo Shingo and Taiichi Ohno devised a new, disciplined, process orientated system which is known today as the “Toyota Production System” or “Lean Manufacturing”. The tools of lean manufacturing have been successfully used within service industry and incorporated into six sigma improvement efforts.
Common lean manufacturing tools include: Value stream analysis, Fishbone diagram, 5 Whys, Scatter diagram, Histograms, 5 S, Just in timE, Production smoothing, SMED, TPM, Kaizen.
Lean manufacturing emphasizes teamwork where the people with the problem come together to search for solutions. The tools are not complex and very little if any statistical knowledge is required. The tools encourage openness and sharing of information. They encourage teams to look for the root causes of problems before jumping to conclusions. They make everybody a participant in designing solutions. Try our online team problem solving tool which does just that.
The title Lean Six Sigma or Lean Sigma reflects the importance of lean tools to the improvement effort. Six sigma has set a high target for acceptable performance. Lean manufacturing tools enable all employees to take an active role in reaching that target. Lean sigma is a combination of the discipline and rigour of statistical analysis and team friendly tools of 'lean'. Together they improve the opportunity for success.
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