Root Cause Analysis Techniques

Root Cause Analysis (RCA)

What is RCA?

Root Cause Analysis is a systematic approach to identifying the underlying causes of problems or incidents to prevent recurrence.

Core Principles

1. Focus on correcting root causes, not symptoms
2. Multiple root causes are possible
3. Facts over assumptions
4. Evidence-based conclusions
5. Prevent recurrence, not assign blame

RCA Techniques

1. Five Whys

Simple technique to drill down to root cause

Process:

1. State the problem
2. Ask "Why did this happen?"
3. For each answer, ask "Why?" again
4. Continue until root cause is identified
5. Usually reaches root cause in 5 iterations

Example:

• Problem: Customer received wrong product
• Why 1: Picker selected wrong item
• Why 2: Items were in wrong bins
• Why 3: Receiving didn't verify placement
• Why 4: No verification process exists
• Why 5: Process never designed

Root Cause: Missing verification process in receiving

2. Fishbone (Ishikawa) Diagram

Visual tool to categorize potential causes

Categories (6 Ms):

• Man (People)
• Machine (Equipment)
• Method (Process)
• Material (Inputs)
• Measurement (Data)
• Mother Nature (Environment)

Process:

1. Draw horizontal arrow (spine)
2. Write problem at the head
3. Draw diagonal bones for categories
4. Brainstorm causes in each category
5. Identify most likely root causes

3. Fault Tree Analysis (FTA)

Top-down, deductive approach using logic gates

Components:

• Top event (undesired outcome)
• AND gates (all inputs needed)
• OR gates (any input sufficient)
• Basic events (root causes)

Process:

1. Define top event
2. Identify immediate causes
3. Use logic gates to connect
4. Continue until basic events
5. Calculate probabilities (optional)

4. Apollo Root Cause Analysis

Principle-based methodology

Steps:

1. Define the problem
2. Create a reality chart (cause-effect)
3. Identify all causes
4. Determine solutions for root causes
5. Implement best solutions

Investigation Best Practices

• Gather evidence promptly
• Interview witnesses
• Document timeline
• Preserve physical evidence
• Avoid confirmation bias
• Consider organizational factors
• Look for systemic issues

Action Planning

• Address root causes, not symptoms
• SMART action items
• Clear accountability
• Verification of effectiveness
• Update policies/procedures