Bowtie Risk Analysis Method
Visual risk analysis methodology that displays the links between causes, controls, and consequences. Excellent for communicating complex risks.
Bowtie Risk Analysis
What is Bowtie?
The Bowtie method is a risk evaluation method that can be used to analyze and communicate risk scenarios. The diagram is shaped like a bowtie, representing the relationship between causes, hazards, consequences, and controls.
Structure of a Bowtie Diagram
Left Side - Threat Analysis
- Threats/Causes: What could cause the hazard to result in a top event?
- Preventive Controls: Barriers that prevent threats from causing the top event
Center - Hazard & Top Event
- Hazard: The central danger or source of potential harm
- Top Event: The moment when control over the hazard is lost
Right Side - Consequence Analysis
- Consequences: What could happen if the top event occurs?
- Mitigating Controls: Barriers that reduce the impact of consequences
Creating a Bowtie
Step 1: Identify the Hazard
What is the source of potential harm in this scenario?
Step 2: Define the Top Event
What is the critical moment when you lose control?
Step 3: Identify Threats (Left Side)
Brainstorm all possible causes that could lead to the top event.
Step 4: Identify Consequences (Right Side)
What are all possible outcomes if the top event occurs?
Step 5: Map Controls
- Preventive controls between threats and top event
- Mitigating controls between top event and consequences
Step 6: Assess Control Effectiveness
Rate each barrier for effectiveness and identify gaps.
Best Practices
- Keep it visual and simple
- Use consistent terminology
- Involve subject matter experts
- Focus on critical barriers
- Link to procedures and policies
- Review and update regularly