Six Sigma is a data-driven problem solving methodology that aims to reduce variation and improve quality. It uses defined processes and statistical tools. There are different belts (white, yellow, green, black, master black) that indicate different experience levels. The main Six Sigma methodologies are DMAIC for improvement projects and DFSS for design projects. DMAIC stands for Define, Measure, Analyze, Improve, Control and guides teams through the problem solving process. DFSS involves defining customer needs, concept design, detailed design, prototyping and control planning. Six Sigma could be used at DONG Renewables for development, warranty issues, out of warranty improvements, experiments, reliability testing and process improvements.