ISO 9001 : 2000Six Sigma is a statistical term that equates to 3.4 defects per one million opportunities. Six Sigma can achieve dramatic improvement in business performance through a precise understanding of customer requirements and the elimination of defects from existing processes, products and services. Key tenets of Six Sigma: Define, Measure, Analyze, Improve, Control. To fully embrace Six Sigma, an organization must work intimately with all internal disciplines in addition to external suppliers and customers.