Experiences with the NUSAP system for multidimensional uncertainty assessment.

This paper discusses recent experiences with the NUSAP system for multidimensional uncertainty assessment, based on case studies that vary in complexity. We show that the NUSAP method, and especially the pedigree analysis part of it, is useful to assess not only parameter uncertainty but also to systematically reflect upon (model) assumptions and problem frames. A diagnostic diagram can be used to synthesize results of quantitative and qualitative analysis. It provides an analytic tool to prioritize uncertainties according to quantitative and qualitative insights in the limitations of available knowledge. We further show that extension of the pedigree scheme to include societal dimensions of uncertainty, such as problem framing and value-laden assumptions, further promotes reflexivity and collective learning. When used in a deliberative setting, NUSAP pedigree assessment has the potential to foster a deeper social debate and a negotiated management of complex environmental problems.