What is Six Sigma
The Six Sigma method is a concept of production management, in which the improvement of work and production processes occurs through the search for and elimination of defects in them. The focus is on those parameters that are most important to the consumer. The concept of Six Sigma was invented by Motorola Corporation in 1986 after it began to receive massive complaints due to the large number of manufacturing defects found in products. Six Sigma methodology gained its popularity after the 90s when Jack Welch made it the main strategy of General Electric.
The Six Sigma methodology includes statistical and quality management methods, as well as a results measurement tool and work teams dedicated to troubleshooting and improving business processes.
You can implement the Six Sigma method in absolutely any company. The implementation principles are as follows:
- Make workflows as predictable as possible (the more predictable they are, the easier they are to control).
- Make all processes measurable and easy to analyze and modify.
- Involve all working groups, from production to marketing.
- Set SMART goals (that is, set measurable goals, such as “Reduce defects by up to 5%”).
- Make decisions based on analysis and statistics only.
Six Sigma methodology: practice and tools
The Six Sigma Rule states that the cost of a defect, if it is not found on time, increases as you move up the process flow. Therefore, a defect detected in production is 100 times cheaper than a defect discovered directly by the consumer. That is why the six sigma approach is implemented in stages based on the DMAIC system, which consists of the following phases:
- define — determine where the problem lies;
- measure — measure the performance of the process and how the problem affects it;
- analyze — analyze what could be the true cause of the failure and how to fix it;
- improve — improve by changing processes to eliminate this cause;
- control — check if the upgrade helped solve the problem.
In addition to a special team, the six sigma system also involves the use of methods and tools from the categories of change management and management itself:
- A business process map that displays the company's resources and tasks to be solved.
- A/B testing, that is, testing solutions on a specific group of people or projects to confirm specific theories.
- Cost-benefit analysis. It is used when choosing between several solutions. As a result, the company chooses the one that offers the most optimal cost-benefit ratio.
- Brainstorming in the "five why’s" format. A Six Sigma team gets together and asks each other questions about inefficient business processes that begin with “why…”. This continues until they find the defect and its cause.
- A CTQ tree. It is a tree diagram of critical features for a given project or process.
In the change implementation phase, Six Sigma requires different tools. The most commonly used are the Pareto curve, Shewhart control chart, regression or variance analysis, etc.
Six Sigma concept: team roles
The Six Sigma method appeals to oriental martial arts, so the gradation within the team is also based on "belts" of different colors, and the structure resembles a pyramid. Specifically, a six sigma team looks like this:
- Executive Leadership is at the top and is responsible for the distribution of tasks, resources and authority. They are the liaison of communication, resolve conflicts and stimulate the efficiency of other team members.
- Champions implement Six Sigma and organize work according to the new rules, also acting as mentors for Master Black Belts.
- Master Black Belts oversee change and implementation of Six Sigma while being in charge of Black Belts.
- Black Belts implement changes, lead the project and carry out the instructions of the Leadership under the supervision of the Master.
- Green Belts are specialists who work on optimizing simple processes that require 50% or less time and resources.
- Yellow and White Belts already have Six Sigma skills and are divided only by the level of awareness (Yellow Belts are more experienced than White Belts). They help others by participating in process upgrades occasionally. The presence of specialists in this category is optional.
Six Sigma as a quality management tool
In practice, the Six Sigma concept is usually implemented in five stages:
- Assess the current situation and determine the goals of the project, as well as the needs of your audience. Based on this, assemble a team of specialists who will find and correct errors that stand in the way of your goals and meeting the needs of customers. Additionally, formalize the areas of responsibility and authority of each team member to avoid internal conflicts.
- Collect up-to-date information about the situation in the company and measure the parameters of processes to assess their current performance. You need to identify the problem and comprehend its depth. Take Motorola's situation, for example - they have great product functionality and service, but a high defect rate.
- Analyze the collected information and identify the factors that influence the occurrence of these problems and the quality of processes. For example, a large number of rejects may be due to outdated production equipment or underqualified employees who inspect goods after assembly.
- Optimize processes so that the problem goes away by itself. First, you need to optimize the process in pilot mode to check if you have chosen the right root cause and way to eliminate it. For example, train staff or replace one of the machine tools to see how the scrap rate changes.
- If trial changes have brought results (say, they reduced the number of rejects), then you can introduce them on a permanent basis and implement them everywhere. However, even if the benefits of changes are confirmed, you should regularly check the statistics and continue to improve other processes consistently, since optimization in one process often leads to defects in another.
To master the application of Six Sigma in practice, you can take the appropriate training by choosing a suitable course.
Six Sigma top practices
In addition to the classic Six Sigma approach described above, there is another variation of the concept called Lean Six Sigma, which combines the classic Six Sigma with the lean manufacturing methodology. The latter technique was invented in Japan in the 1960s by Taiichi Ohno, the founder of Toyota. It is similar to the Eastern philosophy that all business processes should strive for absolute order. And to achieve this, it is necessary that:
- employees are interested in the company’s high performance and have the same conditions for work and self-fulfillment. Then there will be fewer defects;
- management attracts human resources and is not limited to innovation;
- there is an effective corporate culture that is constantly improving to achieve maximum comfort and comradery in the company;
- the company’s leadership finds problems promptly and maintains a friendly environment in the teams.
Lean Six Sigma also borrows all of these principles, as does the Six Sigma principle. Thus, the Six Sigma methodology complements Lean Manufacturing, and together they create a self-consistent and balanced development strategy for any company that increases the quality and value of all business processes.