Six Sigma is a data-driven improvement strategy that views all activities within an organization as processes. Process inputs can be controlled and adjusted to effect significant improvements in process outputs. Six Sigma uses a rigorous and systematic methodology known as DMAIC (define, measure, analyze, improve, and control) and a number of qualitative and quantitative tools. Its goal is to drive process, product, and service improvements for reducing variation and defects. Lean is also an improvement methodology, but with a different focus.