Root cause
Definition
The fundamental, underlying deficiency from which the failure originated. Distinguished from immediate cause (the final physical event) and contributing factors. Root-cause analysis aims to go back far enough in the causal chain to identify the decision or condition that, if corrected, would prevent recurrence.
- Scope in causal chain
- Root cause is identified by tracing back through causes until you reach the fundamental deficiency from which the failure originated.
- Recurrence test
- If correcting it prevents the failure from happening again, it's the root cause. If it doesn't, you likely haven't dug deep enough.
Common questions
How is root cause different from immediate cause?+
Root cause is the fundamental underlying deficiency that started the chain of failure, while immediate cause is the final physical event that triggered the failure. You might find the immediate cause quickly, but it's the root cause that prevents recurrence if corrected.
Why do we care about finding the root cause in investigations?+
Because fixing only the immediate cause or contributing factors often doesn't stop the problem from happening again. Root cause analysis digs deep into the causal chain to find the decision or condition that, if changed, genuinely prevents the failure from recurring.
What makes something a 'root' cause versus just a contributing factor?+
A root cause is the deepest systemic reason. Eliminating it stops recurrence. Contributing factors play a role but aren't sufficient by themselves, so fixing only those won't solve the underlying problem.
Related terms
- 5-Whys
- An iterative questioning technique that moves from a symptom to underlying causes by asking 'why?' repeatedly until a systemic explanation is reached.
- ASTM E860
- Standard Practice for Examining and Preparing Items That Are or May Become Involved in Criminal or Civil Litigation. Specifies documentation requirements and...
- Barrier Analysis
- A method that identifies the physical, administrative, and procedural barriers that should have prevented harm, and asks which barriers were absent, inadequate,...
- Destructive examination
- Testing that consumes or modifies the evidence: sectioning for metallurgical mounts, chemical digestion for composition analysis, mechanical testing to failure. Requires notice...
- Evidence preservation
- The discipline of maintaining physical evidence in its post-incident condition until all parties have had the opportunity to examine it. Includes both...
- Fault Tree Analysis (FTA)
- A top-down, deductive Boolean logic model that works backward from a specific undesired top event through AND/OR gates to identify minimal cut...
- FMEA / FMECA
- Failure Mode and Effects Analysis is a bottom-up, inductive method listing what can fail in each component and the effect on the...
- Hypothesis generation and testing
- The step in failure analysis where possible causes are listed systematically, then each is tested against the physical evidence and engineering calculations....
- Minimal cut set
- In a fault tree, the smallest set of simultaneously failing basic events that is sufficient to cause the top event. Identifies the...
- Non-destructive examination (NDE)
- Inspection methods that do not alter or consume the evidence: visual inspection, photography, dimensional measurement, dye-penetrant testing, ultrasonic testing, and radiography. NDE...
Explained in these topics
- The Failure Investigation ProcessThe fundamental, underlying deficiency from which the failure originated. Distinguished from immediate cause (the final physical event) and contributing factor...
- Root-Cause Analysis MethodsThe deepest systemic reason for a failure. Eliminating it prevents recurrence; eliminating only proximate causes often does not.