Known Project Unknown: Understanding Risk Classification for the Exam

PMBOK v8 Definition

A known-unknown risk is a risk that has been identified and analyzed, but whose probability of occurrence and potential impact are not fully understood. According to PMBOK v8, risks can be classified into four categories: known-known, known-unknown, unknown-known, and unknown-unknown. Known-unknown risks are explicitly recognized as uncertainties that the project team is aware of but cannot predict with certainty. These risks are documented in the risk register and are subject to formal risk response planning. This concept falls under the Project Risk Management Knowledge Area within the Planning Process Group, specifically during the Identify Risks and Perform Quantitative Risk Analysis processes.

Why It Matters for the Exam

The PMI exam frequently tests the distinction between known-unknown and unknown-unknown risks because this classification directly impacts how risks are managed and whether contingency reserves are allocated. Questions often appear in situational scenarios where you must determine the appropriate risk response based on the level of knowledge about the risk. Understanding this classification helps you differentiate between risks that can be planned for (known-unknowns) and those that cannot (unknown-unknowns), which is critical for selecting the correct management reserve versus contingency reserve.

Key Points to Remember (for the exam)

Definition: Known-unknown risks are identified risks with uncertain probability and impact; they are "known" to exist but "unknown" in terms of precise timing, magnitude, or occurrence.
Documentation: All known-unknown risks must be recorded in the risk register using the "cause, event, consequence" structure as specified in PMBOK v8.
Response Planning: Known-unknown risks require proactive risk responses (avoid, mitigate, transfer, accept, exploit, enhance, share, or accept) and are funded through contingency reserves.
Distinction from Unknown-Unknowns: Unknown-unknown risks (emergent risks) cannot be identified in advance and are managed through management reserves and overall project contingency.
Classification Framework: PMBOK v8 defines four risk categories: known-known (managed as scope), known-unknown (managed as risk), unknown-known (hidden facts known by others), and unknown-unknown (emergent risks outside sphere of influence).
Overall Risk Impact: Known-unknown risks contribute to overall project risk, which is the effect of uncertainty on the project as a whole; if overall risk is too high, the organization may cancel the project.
Risk Register Entry: Each known-unknown risk must be described with probability and impact assessments, categorized by RBS or WBS, and assigned to a risk owner.

Typical PMI Exam Example

Scenario: During project planning, the team identifies that a critical supplier may deliver raw materials 2-4 weeks late due to port congestion. The probability is estimated at 30%, but the exact delay duration is unknown. What type of risk is this, and how should it be managed?

Answer: This is a known-unknown risk. It should be documented in the risk register, assessed for probability and impact, and managed through a proactive risk response (e.g., mitigation by identifying an alternative supplier) funded by contingency reserves.

PMI Exam Traps

Trap: Confusing known-unknown risks with unknown-unknown risks. Reality: Known-unknowns are identified and documented; unknown-unknowns are not identified and require management reserves, not contingency reserves.
Trap: Treating all identified risks as requiring immediate response. Reality: Known-unknown risks may be accepted if probability and impact are low; not all identified risks require active response.
Trap: Using management reserves for known-unknown risks. Reality: Contingency reserves are for known-unknowns; management reserves are for unknown-unknowns (emergent risks).
Trap: Assuming known-unknown risks are always threats. Reality: Known-unknown risks can be opportunities (positive risks) that may increase market share, create cost savings, or generate positive environmental impact.

Important PMI Connections

Related Concept	Relationship Type	Exam Attention Point
Risk Register	Output of Identify Risks	Contains all known-unknown risks with cause, event, consequence structure
Contingency Reserve	Funding source	Used specifically for known-unknown risks; part of cost baseline
Management Reserve	Funding source	Used for unknown-unknown risks; not part of cost baseline
Overall Project Risk	Aggregation of all risks	Known-unknowns contribute to overall risk; may lead to project cancellation if too high
Risk Probability and Impact Assessment	Key tool	Assesses likelihood and effect for each known-unknown risk; negative for threats, positive for opportunities

Quick Review Questions

A project manager identifies a risk that a key team member may leave during execution. The probability is unknown, but the impact is high. How should this risk be classified and documented?
During risk identification, the team discovers a potential opportunity to reduce costs by 15% if a new technology is adopted, but the exact savings are uncertain. Is this a known-unknown or unknown-unknown risk? Why?
What is the primary difference between how known-unknown risks and unknown-unknown risks are funded in a project budget?
A project has high overall risk due to several known-unknown threats. According to PMBOK v8, what action might the organization take if the overall risk is deemed too high?
When describing a known-unknown risk in the risk register, what three components must be included according to PMBOK v8?

PMBOK v8 Reference

Section 2.7.2.2 – Identify Risks (including risk classification types: known-known, known-unknown, unknown-known, unknown-unknown)
Section 2.7 – Project Risk Management (overall risk and individual risk definitions)
Section 4 – Inputs and Outputs (risk register structure with cause, event, consequence)