Risk Probability and Impact Assessment in Project Risk Management
PMBOK v8 Definition
Risk probability and impact assessment is a process that evaluates the likelihood that a specific risk will occur and its potential effect on one or more project objectives such as schedule, cost, quality, or performance. Impacts are negative for threats and positive for opportunities. Probability and impact are assessed for each identified individual project risk during interviews or meetings with project team members and knowledgeable persons external to the project.
This activity is part of the Perform Qualitative Risk Analysis process, which belongs to the Risk Management Knowledge Area within the Planning Process Group.
Why It Matters for the Exam
The PMI exam frequently tests your understanding of how probability and impact assessments drive risk prioritization and response planning. Expect scenario-based questions where you must determine which risks require immediate attention based on their probability and impact scores, as well as questions about who participates in these assessments and how organizational risk appetite influences the evaluation criteria.
Key Points to Remember (for the exam)
- Primary Purpose: Assess probability of occurrence AND impact on schedule, cost, quality, or performance for each individual project risk
- Assessment Participants: Project team members AND knowledgeable persons external to the project who are familiar with the types of risks recorded in the risk register
- Risk Appetite Connection: Stakeholder risk appetite is expressed as measurable risk thresholds around each project objective, which inform the definitions of probability and impact levels
- Levels of Detail: Typically five levels for detailed approaches, three levels for simpler processes – the number of levels reflects the degree of detail required
- Watch List: Risks with low probability and impact may be included in the risk register as part of a watch list for future monitoring
- Explanatory Detail: Assumptions justifying the levels assigned must be recorded, and differences in perceived probability/impact among stakeholders should be explored
- Risk Categorization: Risks can be grouped by common root causes, RBS, WBS, project phase, budget, or roles to identify areas of highest risk exposure
Typical PMI Exam Example
A project manager conducts risk probability and impact assessments with the project team and three external subject matter experts. During the meeting, stakeholders disagree on the probability level for a technical risk. The project manager records the different perspectives and the assumptions behind each assessment. Which action should the project manager take NEXT?
Correct answer: Explore the differences in perceived probability levels and document the assumptions justifying the assigned levels.
PMI Exam Traps
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Trap: Confusing risk probability assessment with risk impact assessment Reality: Probability = likelihood of occurrence; Impact = effect on objectives (schedule, cost, quality, performance)
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Trap: Thinking only project team members assess risks Reality: Knowledgeable persons EXTERNAL to the project are also included in the assessment
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Trap: Believing all assessed risks require immediate response planning Reality: Low probability and impact risks may be placed on a watch list for future monitoring
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Trap: Assuming probability and impact definitions are standardized across all projects Reality: Definitions are SPECIFIC to the project context and reflect the risk appetite and thresholds of the organization and key stakeholders
Important PMI Connections
| Related Concept | Relationship Type | Exam Attention Point |
|---|---|---|
| Risk Management Plan | Input (provides definitions) | Contains definitions of probability and impact levels, stakeholder risk appetite, and risk thresholds |
| Risk Register | Output (receives results) | Probability and impact assessments are recorded for each individual risk; low risks go to watch list |
| Risk Breakdown Structure (RBS) | Categorization Tool | Risks grouped by RBS categories to identify areas of highest exposure |
| Perform Quantitative Risk Analysis | Follow-up Process | Risks with high probability/impact scores may proceed to numerical analysis |
Quick Review Questions
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What are the four project objectives typically considered during risk impact assessment?
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When stakeholders disagree on probability levels during an assessment meeting, what should the project manager do?
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What determines the number of probability and impact levels used in a project's risk assessment?
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What happens to risks assessed with low probability and low impact?
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Who must participate in risk probability and impact assessments according to PMBOK v8?
PMBOK v8 Reference
Section 11.3 - Perform Qualitative Risk Analysis Subsection: Risk Probability and Impact Assessment