5 Why Tool – Overview

The 5 Why Tool is a simple but powerful problem-solving method used to identify the root cause of an issue by repeatedly asking “Why?” until the underlying reason is found.

• Typically, five iterations of “Why” are enough to reveal the true root cause, but it may take fewer or more depending on the complexity.

• Widely used in pharmaceutical Quality Management Systems (QMS) for investigations into deviations, OOS (Out of Specification) results, OOT (Out of Trend) data, equipment failures, and process issues.

Steps in Using the 5 Why Tool

1. Define the problem clearly
   Example: A batch failed dissolution testing.

2. Ask “Why?” the problem occurred
   → Because the dissolution time was longer than the specification.

3. Ask “Why?” again for the first answer
   → Because the granules were harder than usual.

4. Repeat until the root cause is found
   → Harder granules because compression force was too high.
   → Compression force was too high because the press operator used an incorrect setting.
   → Incorrect setting because training was inadequate.

5. Identify the Root Cause & Implement Corrective Actions

   • In this example: Inadequate operator training.

   • Corrective action: Improve training program and update SOPs.

Advantages in Pharmaceuticals

• Helps ensure data integrity in investigations.

• Avoids superficial fixes that address symptoms instead of causes.

• Meets GMP and regulatory expectations for thorough root cause analysis.

Example – Pharmaceutical Context

Problem: Sterile injectable batch failed sterility test.
Why 1: Contamination detected in vials.
Why 2: Vials were improperly sealed.
Why 3: Sealing pressure was too low.
Why 4: Equipment calibration was overdue.
Why 5: Preventive maintenance schedule was not followed.
Root Cause: Lapse in preventive maintenance compliance.