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Gedetailleerde leidraad

PBL Guidance for Uncertainty Assessment and Communication
0 Introduction to the Detailed Guidance
1 Problem Framing and Context
2 Process Assessment
3 Environmental Assessment Methods
4 Uncertainty Identification and Prioritization
5 Uncertainty Analysis
6 Review and Evaluation
7 Reporting
References
Acknowledgments
A Appendix: Uncertainty Matrix
A.1 Uncertainty location
A.2 Uncertainty level
A.3 Nature of uncertainty
A.4 Qualification of the knowledge base
A.5 Value-ladenness of choices
A.6 Instructions for filling out the uncertainty matrix
A.7 Uncertainty Matrix
B Appendix: Glossary

A.4 Qualification of the knowledge base

The fourth dimension which is relevant in characterizing the uncertainties concerns the 'qualification of the knowledge base'. This refers to the degree of underpinning of the established results and statements. The term 'established results and statements' can be interpreted in a broad sense here: it can refer to the policy-advice statement as such (e.g. 'the norm will still be exceeded when the proposed policy measures become effective', 'the total annual emission of substance A is X kiloton') as well as to statements on the uncertainty in this statement (e.g. 'the uncertainty in the total annual emission of substance A is ... (95 % confidence interval)'). The degree of underpinning is divided into three classes: weak/fair/strong. If underpinning is weak, this indicates that the statement of concern is surrounded by much (knowledge-related) uncertainty, and deserves further attention. This classification moreover offers suggestions about the extent to which uncertainty is reducible by providing a better underpinning.

Notice that this dimension in fact characterizes the reliability of the information (data, knowledge, methods, argumentations etc.) which is used in the assessment. Criteria such as 'empirical', 'theoretical' or 'methodological' underpinning and 'acceptance/support within and outside the peer community' can be employed for assessing and expressing the level of reliability. If required, a so-called 'pedigree analysis' can be done, which results in a semi-quantitative scoring of the underpinning on the basis of a number of qualitative criteria such as the aforementioned ones (see the tool-catalogue, (van der Sluijs et al., 2003)).