Free Lean Six Sigma Yellow Belt Root Cause Analysis Questions and Answers — Questions and Answers
Question 1: A project team is brainstorming the potential causes of a product defect. To visually organize these potential causes into logical categories such as People, Process, and Equipment, which tool would be most effective?
- Control Chart
- Fishbone (Ishikawa) Diagram (Correct answer)
- SIPOC Diagram
- Pareto Chart
Correct answer: Fishbone (Ishikawa) Diagram
A Fishbone Diagram, also known as a Cause-and-Effect or Ishikawa Diagram, is specifically designed to help teams brainstorm and categorize the potential causes of a problem, making it easy to see the relationships between different factors.
Question 2: An IT team is investigating why a software application crashes frequently. The lead analyst asks, "Why did the application crash?" and the team determines it was due to a memory leak. The lead then asks, "Why was there a memory leak?" This iterative, questioning approach is a direct application of which root cause analysis technique?
- Failure Mode and Effects Analysis (FMEA)
- Brainstorming
- 5 Whys (Correct answer)
- Scatter Plot
Correct answer: 5 Whys
The 5 Whys technique is a simple but powerful tool used to explore the cause-and-effect relationships underlying a problem by repeatedly asking the question "Why?" until the fundamental cause is identified.
Question 3: Which of the following statements best describes the primary objective of Root Cause Analysis (RCA) in the Analyze phase of DMAIC?
- To brainstorm and implement the quickest possible solution.
- To assign blame to the individuals responsible for the process failure.
- To create a detailed map of the current state of the process.
- To identify, verify, and address the fundamental cause of a problem to prevent its recurrence. (Correct answer)
Correct answer: To identify, verify, and address the fundamental cause of a problem to prevent its recurrence.
The core purpose of RCA is to move beyond fixing symptoms and identify the true, underlying cause of an issue. By addressing the problem at its source, the solution will be more effective and prevent the problem from happening again.
Question 4: During a root cause analysis session, a team generates over 30 potential causes for an increase in customer complaints. What is the most logical and effective *next step*?
- Use data and team expertise to prioritize the most likely causes for further investigation. (Correct answer)
- Immediately implement solutions for all 30 potential causes.
- Conclude the Analyze phase and present the list to management.
- Select a cause at random to begin working on a solution.
Correct answer: Use data and team expertise to prioritize the most likely causes for further investigation.
After brainstorming a large number of potential causes, the next critical step is to narrow down the list to the 'vital few' that are most likely contributing to the problem. This is done by using data, process knowledge, and prioritization tools to focus investigative efforts effectively.
Question 5: A key principle of effective Root Cause Analysis is distinguishing between symptoms and the actual root cause. Which of the following is the best example of a symptom?
- An improperly calibrated torque wrench.
- A high rate of product returns from customers. (Correct answer)
- An outdated and incorrect work instruction document.
- Lack of a required preventative maintenance program for a machine.
Correct answer: A high rate of product returns from customers.
A high rate of product returns is a symptom—an observable outcome or indicator that a problem exists. The other options (improper calibration, incorrect instructions, lack of maintenance) are potential root causes that could lead to the symptom of high returns.
Question 6: A team is using a Fishbone Diagram to analyze service delays. They are grouping potential causes under the categories of 'Policies', 'Procedures', 'People', and 'Plant/Technology'. This structure is a common variation of which model?
- The 5 Whys
- The SIPOC Model
- The 4 P's Model (Correct answer)
- The FMEA Model
Correct answer: The 4 P's Model
The 4 P's (or variations like the 6 P's) model, including categories like Policies, Procedures, People, and Plant, is a common framework used for Cause-and-Effect diagrams, especially in service or administrative environments.
Free Lean Six Sigma Yellow Belt Root Cause Analysis Questions and Answers
A project team is brainstorming the potential causes of a product defect.
To visually organize these potential causes into logical categories such as People, Process, and Equipment, which tool would be most effective?