Guidance on Uncertainty Analysis in Scientific Assessments

Abstract

Uncertainty analysis is the process of identifying limitations in scientific knowledge and evaluating their implications for scientific conclusions. It is therefore relevant in all EFSA's scientific assessments and also necessary, to ensure that the assessment conclusions provide reliable information for decision-making. The form and extent of uncertainty analysis, and how the conclusions should be reported, vary widely depending on the nature and context of each assessment and the degree of uncertainty that is present. This document provides concise guidance on how to identify which options for uncertainty analysis are appropriate in each assessment, and how to apply them. It is accompanied by a separate, supporting opinion that explains the key concepts and principles behind this Guidance, and describes the methods in more detail.

Keywords: guidance; scientific assessment; uncertainty analysis.

Figure 1

Check for uncertainties in standardised assessments. Numbered superscripts refer to text notes following the figure. Letters (A, B, C, etc.) are to facilitate reference to specific steps in the figure

Figure 2

Assessing non‐standard uncertainties collectively in standardised assessment

Figure 3

Assessing non‐standard uncertainties for separate parts of the uncertainty analysis using probability bounds

Figure 4

Assessing non‐standard uncertainties for separate parts of the uncertainty analysis using probabilities or distributions

Figure 5

Deciding how to handle uncertainty in a case‐specific assessment. Numbered superscripts refer to text notes following the figure. Letters (A, B, C, etc.) are to facilitate reference to specific steps in the figure

Figure 6

Assessing uncertainties collectively in case‐specific assessments

Figure 7

Combining multiple yes/no questions by expert judgemen

Figure 8

Combining multiple yes/no questions by calculation

Figure 9

Evaluating uncertainties separately for different parts of an assessment involving non‐variable quantities

Figure 10

Evaluating uncertainties separately for different parts of an assessment involving variable quantities

Figure 11

Uncertainty analysis for urgent assessments. Numbered superscripts refer to text notes following the figure. Letters (A, B, C, etc.) are to facilitate reference to specific steps in the figure

Figure 12

Uncertainty analysis to evaluate whether a procedure in a guidance document provides adequate cover for standard uncertainties. Numbered superscripts refer to text notes following the figure. Letters (A, B, C, etc.) are to facilitate reference to specific steps in the figure

Figure 13

Example of probability distribution, quantifying uncertainty about a non‐variable quantity X

Figure 14

Illustration of options for characterising overall uncertainty. See [https://doi.org/10.2903/j.efsa.2018.5122] for detailed explanation

Figure 15

Deciding on approach for taking account of additional uncertainties

Figure 16

Revising a probability expression from earlier steps to take account of additional uncertainties

Figure 17

Evaluate additional uncertainties then combine with an earlier probability expression by calculation