CAPA Root Cause Analysis Methods 2 — Questions and Answers
Question 1: Which tool is best suited for displaying the frequency of defect categories in descending order to prioritize improvement efforts?
- Scatter diagram
- Pareto chart (Correct answer)
- Run chart
- Affinity diagram
Correct answer: Pareto chart
A Pareto chart displays categories in descending order of frequency, helping teams focus on the vital few causes that account for most defects.
Question 2: During a Fault Tree Analysis (FTA), an AND gate indicates that:
- Any one of the input events can cause the output event
- All input events must occur simultaneously for the output event to occur (Correct answer)
- The output event is independent of the inputs
- Only the highest-probability event triggers the output
Correct answer: All input events must occur simultaneously for the output event to occur
An AND gate in FTA means all connected input events must occur together for the top event (failure) to occur.
Question 3: When conducting a '5 Whys' analysis, what is the primary risk practitioners must guard against?
- Asking too few questions
- Jumping to solutions before identifying causes
- Stopping at a symptom rather than the true root cause (Correct answer)
- Involving too many stakeholders
Correct answer: Stopping at a symptom rather than the true root cause
The main risk with 5 Whys is stopping prematurely at a symptom or proximate cause rather than drilling down to the actual root cause.
Question 4: In a cause-and-effect diagram, the 'Methods' bone typically captures:
- Equipment calibration errors
- Standard operating procedures and work instructions (Correct answer)
- Raw material variations
- Personnel training records
Correct answer: Standard operating procedures and work instructions
The Methods bone of a fishbone diagram captures process steps, standard operating procedures, and work instructions that may contribute to the problem.
Question 5: A scatter diagram showing a strong positive correlation between two variables means:
- One variable causes the other
- As one variable increases, the other tends to increase (Correct answer)
- The variables are unrelated
- A corrective action is not required
Correct answer: As one variable increases, the other tends to increase
A positive correlation indicates that as one variable increases, the other tends to increase, though correlation does not imply causation.
Question 6: Which RCA technique uses a structured tree diagram to identify all possible ways a system could fail?
- 5 Whys
- Fault Tree Analysis (Correct answer)
- Affinity diagram
- SIPOC analysis
Correct answer: Fault Tree Analysis
Fault Tree Analysis uses a deductive top-down tree diagram to map all possible failure paths leading to an undesired top event.
Question 7: The 'Measurement' category in a fishbone diagram addresses which source of variation?
- Supplier material inconsistencies
- Gauge accuracy, calibration, and data collection methods (Correct answer)
- Environmental temperature and humidity
- Operator skill differences
Correct answer: Gauge accuracy, calibration, and data collection methods
The Measurement bone examines whether instruments, calibration, and data collection methods could be introducing error or variation.
CAPA Root Cause Analysis Methods 2
Which tool is best suited for displaying the frequency of defect categories in descending order to prioritize improvement efforts?