Probability and Impact Matrix
The probability and impact matrix is a grid that maps the probability of a risk occurring against its potential impact on project objectives, producing a risk score used to prioritize risks.
Explanation
The probability and impact matrix (P&I matrix) is a key tool in qualitative risk analysis. It combines predefined probability ratings (e.g., 0.1, 0.3, 0.5, 0.7, 0.9) with impact ratings on a similar scale. The intersection of a risk's probability and impact values yields a risk score, which determines whether the risk is categorized as high, moderate, or low priority.
The matrix is defined in the risk management plan, including the scales, thresholds, and color-coding (often red/yellow/green). Separate matrices may be created for different project objectives such as cost, schedule, scope, and quality, since a risk might have high impact on schedule but low impact on cost.
Risks in the high-priority (red) zone receive immediate attention—detailed analysis, response strategies, and dedicated risk owners. Moderate (yellow) risks are monitored and may have contingency plans. Low (green) risks are placed on a watch list and reviewed periodically.
Key Points
- •Combines probability and impact ratings to produce a risk score
- •Defined in the risk management plan with scales and thresholds
- •Separate matrices may exist for cost, schedule, scope, and quality
- •Categorizes risks into high, moderate, and low priority zones
Exam Tip
Know how to calculate a risk score: Risk Score = Probability x Impact. A risk with P=0.7 and I=0.8 scores 0.56, which typically falls in the high-priority zone.
Frequently Asked Questions
Related Topics
Perform Qualitative Risk Analysis
Perform Qualitative Risk Analysis is the process of prioritizing individual project risks by assessing their probability of occurrence and impact on project objectives.
Risk Management Plan
The risk management plan is a component of the project management plan that describes how risk management activities will be structured and performed. It is the output of the Plan Risk Management process.
Risk Categorization
Risk categorization is the grouping of risks by their source, affected area, or other useful criteria to identify concentrations of risk exposure and common root causes.
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