What Is an Influence Diagram

Understanding Influence Diagrams for Stakeholder Mapping, Risk Assessment, and ISO 45001 Decision Support

Updated March 2025

An Influence Diagram is a visual modelling tool used to represent the relationships between decisions, uncertainties, and outcomes within a system. It helps simplify complex decision-making by showing how various factors influence one another—especially in risk assessment, stakeholder strategy, and operational planning.

In the context of ISO 45001-compliant Occupational Health & Safety (OH&S) systems, Influence Diagrams are valuable for understanding the systemic impact of stakeholder behaviours, identifying critical risks, and improving safety-related decision-making.

Key Components of an Influence Diagram

Why Use Influence Diagrams?

Influence Diagrams help stakeholders and safety professionals:

Unlike linear tools like flowcharts or decision trees, Influence Diagrams emphasise probabilistic relationships and interdependencies, making them ideal for addressing uncertainties in operational safety, stakeholder engagement, and regulatory planning.

Application Example: OH&S Stakeholder Impact

In an ISO 45001 implementation project, an Influence Diagram can be used to map how worker feedback (uncertainty) affects safety policy design (decision), which in turn impacts incident reduction (outcome). Arrows can trace how indirect stakeholder attitudes or external pressures influence the system’s final performance.

Influence Diagrams focus on relationships and probabilities, rather than process steps. They are ideal for visualising how uncertain or complex variables affect each other.

Yes. Influence Diagrams are useful in ISO 45001 for risk assessment (Clause 6.1), evaluating stakeholder effects (Clause 4.2), and planning controls that respond to systemic risks and interdependencies.

They help visualise how stakeholder behaviours, interests, and external inputs affect decisions and outcomes—supporting more informed, inclusive planning and engagement strategies.