HKSM
Probability Impact Grid
A matrix used to evaluate risks by rating how likely they are to occur and how much they could affect project objectives. Each dimension receives a numeric score, and the two scores are multiplied to produce a severity value used to rank and prioritize risks.
Key Points
- Displays risks on a grid with probability on one axis and impact on the other.
- Uses numeric scales (for example, 1-5) to score probability and impact independently.
- Multiplies the two scores to calculate a risk severity score for prioritization.
- Supports setting thresholds to group risks as low, medium, or high for action.
Example
During sprint planning, the team scores three risks: vendor delay (probability 4, impact 5 = severity 20), test environment outage (probability 2, impact 4 = severity 8), and scope churn (probability 3, impact 3 = severity 9). The vendor delay, with the highest score, is prioritized for immediate response planning.
PMP Example Question
A project manager assigns separate numeric ratings for probability and impact to each identified risk and multiplies them to rank which risks to address first. Which tool is being used?
- Probability Impact Grid
- Risk register
- Monte Carlo simulation
- Cause-and-effect diagram
Correct Answer: A — grid that multiplies probability and impact to rank risks
Explanation: The Probability Impact Grid scores probability and impact independently and multiplies them to produce a severity rating used to prioritize risks.
