Who? - Identity individuals associated with the problem. Characterize customers who are complaining. Which operators are having difficulty?
What? - Describe the problem adequately. Does the severity of the problem vary? Are operational definitions clear (e.g. defects)? Is the measurement system repeatable and accurate?
When? - Identify the time the problem started and its prevalence in earlier time periods. Do all production shifts experience the same frequency of the problem? What time of year does the problem occur?
Where? - If a defect occurs on a part, where is the defect located? A location check sheet may help. What is the geographic distribution of customer complaints?
Why? - Any known explanation(s) contributing to the problem should be stated.
How? - In what mode or situation did the problem occur? What procedures were used?
How Many? - What is the extent of the problem? Is the process in statistical control?