Root Cause Analysis: Why “Human Error” Is Not the Root Cause

Introduction

Root cause analysis (RCA) is a critical element of corrective action processes in ISO 9001, ISO 14001, ISO 45001, and ISO/IEC 17025.

Despite its importance, one of the most common “root causes” identified during investigations is simply:
“Human error.”

While human error may describe what happened, it rarely explains why it happened.

Why “Human Error” Is Not a Root Cause

Labeling an issue as human error does not address:

• System weaknesses
• Process gaps
• Poor design of workflows
• Inadequate controls
• Organizational factors (e.g., workload, communication)

Example:

Problem: Incorrect result reported
Root cause stated: “Analyst made a mistake”

👉 This does not explain:

• Why the mistake occurred
• Why it was not detected
• What allowed it to happen

Common Gaps in Root Cause Analysis

• Stopping analysis too early
  The first explanation is accepted without deeper investigation.
• Focusing on individuals instead of systems
  Blaming employees rather than identifying systemic issues.
• Lack of structured methodology
  No use of tools such as 5 Whys or cause analysis.
• Pressure to close findings quickly
  RCA treated as an administrative task.
• Weak linkage to corrective actions
  Actions do not address underlying causes.

What Effective Root Cause Analysis Looks Like

• Understanding the system, not just the event
• Identifying contributing factors
• Linking causes to process weaknesses
• Supporting meaningful corrective actions

Practical, Step-by-Step Approach

Step 1: Clearly Define the Problem

• What happened?
• When and where?
• How was it detected?

Step 2: Ask “Why” Multiple Times

Use the 5 Whys technique:

• Why did this happen?
• Why was that possible?
• Why was it not prevented?

Step 3: Identify Contributing Factors

Consider:

• Process design
• Training and competency
• Work environment
• Equipment and tools
• Communication

Step 4: Look for System Weaknesses

Ask:

• What control failed?
• What control was missing?
• What allowed this to go undetected?

Step 5: Link to Corrective Actions

Ensure actions:

• Address root causes
• Improve processes
• Prevent recurrence

Practical Example

Problem: Sample mix-up

Instead of:

❌ Root cause: “Technician error”

Better analysis:

• ✔ Labels unclear
• ✔ No verification step
• ✔ High workload
• ✔ Poor workspace organization

Key Insight

Human error is usually the result of system weaknesses — not the cause.

Conclusion

Effective root cause analysis requires looking beyond individuals and focusing on systems.

Organizations that do this well:

• Prevent recurrence
• Improve processes
• Build stronger management systems