Gedetailleerde leidraad

4 Uncertainty Identification and Prioritization

Central in this step is highlighting areas in the uncertainty matrix (appendix A) that need attention in the problem at hand. The matrix is spanned by a table which distinguishes five dimensions for characterizing uncertainties: on the one hand 'location' of uncertainty is put forward as a central dimension for indicating 'where' uncertainty will occur, while four additional dimensions or features are used to characterize how the uncertainties at these specific locations can be further characterised:

• The 'location' scale distinguishes between context (ecological, technological, economic, social and political representation and embedding), expert judgment and considerations (storylines, narratives, advices), models (including model inputs (input data, driving forces, input scenarios), model structure and model parametrization, model implementation (hardware and software) issues), data (measurements, monitoring and survey data) and outputs (outcomes of interest such as indicators; statements etc.).
• The four additional dimensions which are used to characterize the specific uncertainties at their various locations are: (a) 'level of uncertainty' as a means to express how uncertainty can be classified on the gradual scale from 'knowing for certain' to 'complete ignorance', (b) 'nature of uncertainty' to express whether uncertainty primarily stems from inherent system variability or from deficiencies in our knowledge and information, (c) 'qualification of knowledge base' referring to the level of underpinning and backing of involved results/statements, and finally (d) the 'value-ladenness of choices' involved in the study at hand e.g. choices concerning the way the scientific questions are framed, data are selected, interpreted and rejected, methodologies and models are devised and used, explanations and conclusions are formulated etc.

In a separate document (Tool Catalogue for Uncertainty Assessment, van der Sluijs et al., 2003) we have compiled a description of available tools for addressing uncertainty, providing information on:

• The types of uncertainty that the tool addresses
• The resources required to use the tool
• Strengths and limitations of each tool
• Some guidance on the application of the tools and on their complementarity with other tools
• Pitfalls of each tool
• References to handbooks, user-guides, case studies, web-sites, and experts

Once uncertainties have been identified, the uncertainty tool(s) which are suitable to cope with them can be selected on basis of the information in the uncertainty tool catalogue.

1. Work through the uncertainty matrix (appendix A) to identify uncertainties. List the uncertainties indicated from the uncertainty matrix and from table 4 in the left column of table 5. Next, identify the tools best suited for addressing each uncertainty in the right column in table 5.

 Table 5: Uncertainties and tools to address them