Conditional uncertainty analysis and implications for decision making: the case of WIPP

Area of Science:

• Risk Assessment and Management
• Decision Analysis
• Environmental Science

Background:

• Uncertainty analyses are crucial for risk management but can be misinterpreted.
• Conditional analyses, using conservative assumptions, pose interpretation challenges.
• Misinterpretation can lead to suboptimal decisions and resource allocation.

Purpose of the Study:

• To examine the misinterpretation of conditional uncertainty analyses.
• To analyze the impact of conservative assumptions on risk curve percentiles and outcome intervals.
• To highlight challenges in comparing and using results from conditional analyses for policy-making.

Main Methods:

• Examination of two cases of conditional uncertainty analysis.
• Focus on conditional risk curves and intervals derived from conservative assumptions.
• Illustration using the performance assessment of the Waste Isolation Pilot Plant (WIPP).

Main Results:

• Conditional risk curves may be misinterpreted as marginal distributions, underestimating true risk.
• Intervals from conservative assumptions obscure the likelihood of outcomes and possible benign scenarios.
• Results from conditional analyses are difficult to compare with other risk assessments.

Conclusions:

• Conditional uncertainty analyses require careful interpretation to avoid misrepresenting risk.
• Conservative assumptions can distort risk perception, impacting policy and decision-making.
• Standardized methods for reporting conditional analyses are needed for better comparability and use.