Root Cause Analysis
Short for RCA
A structured investigation method that identifies the underlying cause of a problem rather than treating its symptoms.
Definition
Root Cause Analysis (RCA) is the investigative technique at the heart of effective CAPA programs, incident investigations, and continuous improvement systems. Common RCA methods include the '5 Whys' (asking 'why' repeatedly until reaching an actionable cause), Fishbone/Ishikawa diagrams (mapping contributing factors across categories like people, process, equipment, environment), Fault Tree Analysis, and Pareto Analysis. The goal is always the same — identify the systemic cause so the corrective action eliminates the problem rather than masking it.
Why it matters
Weak RCA is the single most common reason corrective actions fail to prevent recurrence. 'We retrained the operator' is almost never a root cause — it's a symptom of a procedural, design, or management system failure. ISO 9001, FDA, and most quality frameworks expect RCA documentation that demonstrates systemic thinking. A well-written RCA SOP defines which incidents require RCA, what methods to use, and who must approve the finding before corrective action is committed.
Related terms
A structured process for investigating quality problems, implementing fixes, and preventing recurrence. Core to ISO 9001 and FDA quality systems.
The international standard for quality management systems, requiring documented procedures, continuous improvement, and risk-based thinking.