Six Sigma
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Six Sigma is a data-driven methodology for eliminating defects and reducing variation in processes to achieve near-perfect quality.
Definition
Six Sigma is a disciplined, data-driven methodology for eliminating defects and reducing variation in any process. Originally developed at Motorola in the 1980s and popularized by General Electric, the approach uses statistical methods to measure and improve operational performance. The term "Six Sigma" refers to a statistical concept where a process produces only 3.4 defects per million opportunities—representing near-perfect quality. Beyond statistics, Six Sigma provides a structured problem-solving framework (DMAIC) and a certification system for practitioners.
Examples
A semiconductor manufacturer was experiencing a 2% defect rate in chip production, costing $15 million annually in scrap and rework. Using Six Sigma methodology, they identified that temperature variation in one oven was the primary cause. After installing better controls, defects dropped to 0.02%, saving $14 million per year.
Key Points
- Six Sigma uses DMAIC (Define, Measure, Analyze, Improve, Control) as its core problem-solving methodology
- The goal is 3.4 defects per million opportunities, representing 99.99966% accuracy
- Projects are led by trained practitioners: Yellow Belts, Green Belts, Black Belts, and Master Black Belts
- Success requires strong data collection and statistical analysis capabilities
Common Misconceptions
Six Sigma is only for manufacturing. While born in manufacturing, Six Sigma applies to any repeatable process—healthcare, finance, software, logistics. If you can define a defect and measure it, you can apply Six Sigma.
Six Sigma replaces Lean. Six Sigma and Lean are complementary. Lean focuses on speed and waste elimination; Six Sigma focuses on quality and variation reduction. Many organizations use "Lean Six Sigma" to combine both approaches.