ANSWER
Fault Tree Analysis (FTA) is a systematic, top-down method used to identify the root causes of potential system failures. It visually maps how different component failures, human errors, or process faults can combine to produce an undesirable event—known as the “top event.”
FTA helps analysts understand why a failure might occur, how likely it is to occur, and what corrective or preventive actions can reduce that likelihood. It is widely used in safety-critical industries such as aerospace, healthcare, automotive, manufacturing, and finance (for risk modeling).
1. Core Concept
The process starts by defining a top-level failure, such as “system outage” or “patient record mismatch.” This top event is then broken down into intermediate and basic events through logical relationships represented by AND and OR gates:
- AND Gate: The top event occurs only if all input events occur.
Example: A system crash might occur only if both the server fails and the backup fails.
- OR Gate: The top event occurs if any one of the input events occurs.
Example: A data error could result from either a software bug or user input error.
The resulting fault tree is a graphical model that shows how combinations of smaller failures can lead to a major system breakdown.
2. Why It Matters
For a business analyst, Fault Tree Analysis provides a structured way to link technical issues to business risks. It supports decision-making by quantifying which failure paths pose the greatest risk to operations, compliance, or customer outcomes.
For example, in a banking system, the top event might be “Loan processing failure.” The analyst can decompose this into causes such as:
- API integration failure (system issue)
- Incorrect data mapping (process issue)
- User authorization error (human or policy issue)
By visualizing these interdependencies, stakeholders can see which root causes are most critical and prioritize mitigation steps like improved data validation, system monitoring, or staff training.
3. Analytical Value
FTA isn’t just qualitative—it can also be quantitative. Each basic event can be assigned a probability of occurrence. When combined through the logic gates, these probabilities help estimate the overall risk of the top event. This makes FTA a powerful tool for risk quantification, reliability engineering, and control design.
For business analysts, FTA aligns with key skills such as:
- Root cause analysis (understanding dependencies and triggers)
- Impact assessment on KPIs and service levels
- Validation of preventive controls within business or IT processes
