Validating a Meta-Model: The Example of Sustainability Impact Assessment Tools (SIAT) for European Land Use Analysis

The integrated meta-modelling approach SIAT is the central product of the project SENSOR (6th EU Framework Program), which innovates ex-ante impact assessments (IA) of European policy instruments. Analytical focus of this article is how to cope with the problem of system complexity regarding consistency and reliability of scenario outcomes. Thus, the iterative process of validating the meta-model SIAT is described in respect of undertaken measures. SIAT enables end users to assess regional effects of land-use relevant EU-policy strategies and evaluate the impacts against sustainability criteria. SIAT focuses analytically on crosssectoral trade offs of the six sectors agriculture, forestry, energy, transport, nature conversation and tourism. Policy effects of multifunctional land use are measured by sustainability indicators. Risk assessments are conducted by defining sustainable tolerance limits that determine the allowable range of sustainable developments. The model design of SIAT is composed of mathematical response protocols, which are derived by quantitative modelling techniques solving iteratively linked components of a model framework. Complementary knowledge rules assure indicator calculations beyond modelling capacities in the form of qualitatively described responses as decision trees. All integrated methods need consistency checks across different scales from grid to EU-level and among indicator aggregations. This article concludes that the complex meta-model system SIAT needs a set of individually applied measures to be able to assure reliable policy scenario results. Potential inconsistencies can be minimised by calibrating and validating used single models as well as the interacting model framework, but complementary ex-post evaluation of model results at disaggregated level of sensitive regions with stakeholder involvements is additionally an inalienable procedure.