HKSM
Influence Diagram
A visual model that maps cause-and-effect relationships, the sequence of events over time, and how different variables interact to shape possible outcomes.
Key Points
- Shows causal influences and time ordering among decisions, uncertainties, and results.
- Uses nodes for variables/events and arrows to indicate direction of influence.
- Clarifies assumptions, dependencies, and drivers of risk before quantifying them.
- Often precedes or complements decision trees and other risk analysis techniques.
Example
On a construction project, the team sketches an influence diagram where weather conditions affect concrete curing, which influences the foundation schedule, which then affects framing start dates and overall project duration. Supplier reliability influences delivery dates, which impacts schedule risk and potential overtime costs. Inspections influence rework, which in turn affects budget and timeline.
PMP Example Question
During qualitative risk analysis, the team wants a visual model to depict how supplier reliability, weather, and inspection results could impact the schedule and cost over time. Which tool should they use?
- Cause-and-effect (Ishikawa) diagram
- Precedence diagram (network diagram)
- Influence diagram
- Control chart
Correct Answer: C — Influence diagram
Explanation: An influence diagram displays causal influences, timing, and relationships among variables and outcomes, making it ideal for visualizing how factors drive schedule and cost risk.
