In 1986, Motorola developed a set of techniques and tools to minimize variability in manufacturing and improve business processes. Known as Six Sigma, this business methodology seeks to improve not only the effectiveness of business processes but also product quality throughout an organization.
The Six Sigma approach is structured and largely data-driven. It has also been described as project- and customer-focused, since it strives to eliminate any and all errors during the production and delivery of products. The Six Sigma methodology became increasingly popular during the 1990s when Fortune 500 firms such as General Electric incorporated Six Sigma tools and techniques into business strategy to reduce costs and improve product quality.
What is Six Sigma?
The term “Six Sigma” is defined as, “A measure of quality that strives for near perfection.” As a statistical concept, Six Sigma is a metric that represents the variation in a business process and its ability to meet customer expectations. Moreover, a business process achieves Six Sigma when it produces no more than 3.4 defects—that is, anything that falls outside of customer specifications—per million opportunities. In theory, a manufacturing process operating at the Six Sigma level should produce outcomes that are virtually defect-free.
From government agencies to schools and banks, Six Sigma has been used to reduce errors, improve quality and productivity in organizations all over the world. The Six Sigma Academy estimates that individuals trained in the Six Sigma methodology complete four to six projects a year, and save companies an average of $230,000 per project. General Electric reported saving approximately $10 billion over the course of five years after implementing the Six Sigma methodology within its organization.
Six Sigma Methodologies: DMAIC and DMADV
While various frameworks are used to implement Six Sigma, there are two primary models used for guiding Six Sigma projects: DMAIC and DMADV. Both sub-methodologies strive to eliminate errors and achieve revenue targets. However, how practitioners apply DMAIC and DMADV, as well as the phases that comprise each sub-methodology, is where they diverge.
The DMAIC Project
DMAIC is used to improve existing products and processes within an organization. For example, a DMAIC project under Six Sigma may aim to rectify a process that fails to meet customer expectations and performance standards.
There are five phases that makeup DMAIC projects:
- Define project objectives and customer deliverables.
- Measure the process using performance metrics.
- Analyze the data and determine the underlying causes of the defects.
- Improve the process by eliminating defects and aligning processes with business goals.
- Control the production process by adjusting for ongoing improvement.
The DMADV Process
The second project methodology, DMADV, should be used to develop new products and processes at Six Sigma quality levels, or improve existing products and processes that fail to address customer requirements. This is especially true for products and processes that require more than just incremental improvements.
DMADV (also known as DFSS, or “Design for Six Sigma”) encompasses five phases:
- Define design goals that align with customer demands and business strategy.
- Measure and identify characteristics that are Critical To Quality (CTQ), whether these are product or production capabilities.
- Analyze metrics to assess how products and processes can better align with customer needs.
- Design a product or process that is best suited to customer needs based on the analysis performed in the Analyze phase.
- Verify that design addresses customer specifications through pilot runs and ongoing improvements.
Implementing Six Sigma Principles
Since the introduction of the Six Sigma Methodology, organizations that use Six Sigma have involved stakeholders beyond the statisticians and engineers that have traditionally managed the manufacturing process. Likewise, Six Sigma involves multiple roles at all levels to help successfully carry out Six Sigma projects. These key players are identified as:
- Champions: They select and oversee the implementation of Six Sigma projects. These individuals typically occupy top management roles within an organization.
- Master Black Belts: They are skilled in Six Sigma tools. They ensure that said tools are implemented consistently across an organization’s departments and functions. Master Black Belts are devoted to implementing Six Sigma full-time.
- Black Belts: They work under Master Black Belts and serve as mentors to Green Belts. Their roles focus on leading and executing projects with special tasks.
- Green Belts: They work under the guidance of Black Belts and assist with Six Sigma implementation as part of their daily job.
Getting Six Sigma Certification
There is no single official certification body or standard for the Six Sigma Methodology. Nevertheless, General Electric, Motorola and other companies have developed their own in-house certification programs. Additionally, the responsibilities and qualifications for Green Belts, Black Belts, and other Six Sigma implementation roles may vary across companies and industries.
The professional associations offer exams and issue certificates of completion for Six Sigma implementation roles. Six Sigma consultants are also available to companies interested in implementing Six Sigma in their organizations.