Table of Contents
Why Are Root Cause Analysis Tools So Valuable in Six Sigma?
Prepare for your Six Sigma Green Belt exam by understanding the value of root cause analysis (RCA) tools. Learn how tools like the 5 Whys and Fishbone diagrams help uncover and address the true sources of problems, preventing recurrence and leading to effective, sustainable improvements.
Question
Why are root cause analysis tools valuable?
A. They quickly assign blame to individuals
B. They are used only after project completion
C. They uncover and address the true sources of problems
D. They increase reporting complexity
Answer
C. They uncover and address the true sources of problems
Explanation
Root cause tools identify actual causes behind defects. The fundamental value of root cause analysis (RCA) tools in Six Sigma is their ability to guide a project team beyond the surface-level symptoms of a problem to identify and resolve the underlying causes, which prevents the problem from recurring.
Moving from Symptoms to Solutions
When a defect or process failure occurs, it is often just a symptom of a deeper issue. Simply fixing the symptom—for example, reworking a defective part—is a temporary and inefficient solution because it does not address what caused the defect in the first place. Root cause analysis provides a structured, systematic way to investigate the chain of events that led to the failure. By repeatedly asking “Why?” and drilling down through layers of causality, RCA tools help teams pinpoint the fundamental breakdown in the process. Addressing the problem at its root is the only way to create a permanent and effective solution.
Common Root Cause Analysis Tools
During the Analyze phase of a DMAIC project, Green Belts use several key tools to conduct root cause analysis:
- The 5 Whys: A simple but powerful technique where the investigator repeatedly asks “Why?” to peel back the layers of a problem. The goal is to continue asking until the root cause is identified, which often occurs by the fifth “Why.”.
- Fishbone Diagram (Ishikawa Diagram): This visual tool helps teams brainstorm and categorize all the potential causes of a problem. The causes are typically grouped into major categories like Manpower, Method, Machine, Material, Measurement, and Environment (the 6Ms), which helps to organize the analysis and ensure no potential cause is overlooked.
- Pareto Chart: This is a combination bar and line chart that helps to identify the “vital few” causes that are responsible for the majority of the problems (the 80/20 rule). It allows a team to prioritize their efforts on the causes that will have the greatest impact when solved.
Analysis of Incorrect Options
A. They quickly assign blame to individuals: This is contrary to the philosophy of both Six Sigma and root cause analysis. The focus is always on identifying flaws in the process, not on blaming people. A core principle is that most problems are caused by process issues, not by individual negligence.
B. They are used only after project completion: This is incorrect. Root cause analysis is the central activity of the Analyze phase, which occurs in the middle of a DMAIC project. It must be completed before any solutions can be developed in the Improve phase.
D. They increase reporting complexity: While the analysis can be detailed, the goal of RCA tools is to bring clarity, not complexity. Visual tools like the Fishbone diagram are specifically designed to simplify a complex problem by organizing potential causes in a logical, easy-to-understand format.
Six Sigma Green Belt: Apply, Analyze & Improve certification exam assessment practice question and answer (Q&A) dump including multiple choice questions (MCQ) and objective type questions, with detail explanation and reference available free, helpful to pass the Six Sigma Green Belt: Apply, Analyze & Improve exam and earn Six Sigma Green Belt: Apply, Analyze & Improve certificate.