DOE (Design of Experiments)

Structured experimental methodology that systematically varies multiple input factors to determine their effect on output variables. More efficient than one-factor-at-a-time testing because it reveals interactions between factors. Common designs include full factorial, fractional factorial, and response surface methods. Used in Six Sigma Improve phase and advanced problem-solving when multiple variables interact. Requires statistical expertise but yields powerful insights. Mentioned in your Step 4 RCA article as quantitative multi-variable analysis approach.