Figure Example Project: Probability and Impact Matrix with Scoring Scheme

PMBOK v8 Definition

The Probability and Impact Matrix is a grid for mapping the probability of each risk occurrence and its impact on project objectives if that risk occurs. Risks are prioritized according to their potential for meeting project objectives, and the matrix provides a scoring scheme that combines probability and impact ratings to assign an overall risk score. This tool is used in the Perform Risk Analysis process within the Risk Performance Domain.

Why It Matters for the Exam

The Probability and Impact Matrix appears frequently on the PMI exam in questions about risk prioritization, risk scoring, and the Perform Risk Analysis process. You will encounter it in situational questions where you must determine which risks need immediate response based on their combined probability and impact scores, as well as in process-focused questions about the tools and techniques for quantitative and qualitative risk analysis.

Key Points to Remember (for the exam)

• Main Process: Perform Risk Analysis (Risk Performance Domain)
• Main Output: Prioritized list of individual project risks with assigned risk scores
• Key Tool: Probability and Impact Matrix with Scoring Scheme
• Scoring Calculation: Risk Score = Probability × Impact (using predefined scales)
• Common Confusion: Not confusing this with Perform Quantitative Risk Analysis—this matrix is for qualitative prioritization, not numerical modeling
• Critical Distinction: The matrix uses ordinal scales (e.g., Low/Medium/High or 1-5), not continuous numerical values
• Exam Favorite: The matrix can be customized for different project objectives (cost, time, scope, quality)

Typical PMI Exam Example

A project manager identifies a risk of supplier delay with a probability rating of 0.5 and an impact rating of 0.7 on the project schedule. Using the Probability and Impact Matrix with a scoring scheme where scores above 0.35 require immediate response, the project manager calculates the risk score as 0.35 (0.5 × 0.7) and determines this risk falls into the high-priority category requiring a risk response plan.

PMI Exam Traps

• Trap: Confusing the Probability and Impact Matrix with the Risk Register

  • Reality: The matrix is a tool to prioritize risks; the Risk Register is the document that captures all identified risks and their analysis results

• Trap: Thinking the matrix replaces quantitative analysis

  • Reality: The matrix provides qualitative prioritization; quantitative analysis uses numerical modeling (e.g., Monte Carlo simulation) for detailed probability distributions

• Trap: Assuming one matrix fits all projects

  • Reality: The matrix should be customized for each project's specific objectives, risk appetite, and organizational thresholds

• Trap: Confusing risk score with risk urgency

  • Reality: A high risk score indicates high priority, but urgency also depends on when the risk might occur and how quickly response is needed

Important PMI Connections

Quick Review Questions

1. In which process is the Probability and Impact Matrix with Scoring Scheme used?
2. How is the risk score calculated when using this matrix?
3. What is the difference between the Probability and Impact Matrix and the Risk Register?
4. Why might a project manager need to customize the matrix for a specific project?
5. What type of scales (ordinal or continuous) are used in the Probability and Impact Matrix?

PMBOK v8 Reference

Section 5.0 - Risk Performance Domain Figure 5-14: Example Probability and Impact Matrix With Scoring Scheme (Page 187)