Root Cause Analysis
Root Cause Analysis
Root Cause Analysis (RCA) is a structured method used to identify the underlying cause of a problem so that long-term, effective solutions can be implemented—rather than just treating symptoms. Root Cause Analysis is a problem-solving approach that focuses on finding why an issue occurred and eliminating the cause so the problem does not recur.
Root Cause Analysis Tools
1️⃣ 5 Whys Analysis
A simple method where you ask “Why?” repeatedly (typically 5 times) until you reach the true cause.
Best for: Simple or linear problems.
2️⃣ Fishbone Diagram (Ishikawa / Cause-and-Effect)
A visual tool that groups causes into categories such as:
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People
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Process
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Machine
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Materials
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Measurement
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Environment
Best for: Complex/large problems; brainstorming sessions.
3️⃣ Pareto Analysis (80/20 Rule)
Uses data to identify the most significant causes that contribute to most of the problem.
Best for: Prioritizing which issues to fix first.
4️⃣ Fault Tree Analysis (FTA)
A top-down, logical diagram showing how failures combine to cause a larger problem.
Uses AND/OR gates.
Best for: Engineering, safety, reliability studies.
5️⃣ Failure Mode and Effects Analysis (FMEA)
A structured method to identify:
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Failure modes
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Effects
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Severity (S)
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Occurrence (O)
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Detection (D)
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Risk Priority Number (RPN = S × O × D)
Best for: Manufacturing, engineering design, process analysis.
6️⃣ Scatter Diagram
Plots data points to see correlation between two variables (e.g., temperature vs. defect rate).
Best for: Identifying patterns or relationships.
7️⃣ Histogram
A graphical tool to understand distribution, variation, and frequency of data.
Best for: Quality control and statistical analysis.
8️⃣ Control Charts
Used in Statistical Process Control (SPC).
Shows variations over time and detects unusual patterns.
Best for: Monitoring process stability.
9️⃣ The 8D (Eight Disciplines) Approach
A structured 8-step problem-solving method:
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Team formation
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Problem description
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Containment actions
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RCA
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Corrective actions
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Verification
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Prevention
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Recognition
Best for: Automotive, manufacturing, customer complaints.
🔟 Brainstorming
Team-based idea generation to explore all possible causes.
Often used before Fishbone or FTA diagrams.
1️⃣1️⃣ Root Cause Mapping
A visual mapping method linking symptoms → causes → root causes → actions.
Best for: Process improvement teams.
1️⃣2️⃣ Barrier Analysis
Examines how controls/barriers failed (or didn’t exist).
Best for: Safety incidents and accident investigations.
1️⃣3️⃣ Kepner–Tregoe Analysis
A systematic framework for:
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Situation appraisal
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Problem analysis
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Decision analysis
Best for: Decision making, complex high-impact issues.
