8.Ability to collect, compile and analyze data (using the appropriate six sigma methods and techniques); to determine both the actual root causes of identified problems and required corrective (preventive) actions to prevent recurrence. 21.Lead complex investigations into product and process nonconformances, field issues, and test escapes, applying advanced problem-solving tools (e.g., 5-Why, Ishikawa, DOE, regression analysis, fault tree analysis) to identify true root cause.