DISCUSS: A soft computing approach to spatial disaggregation in

For more than three decades cost-benefit analysis (CBA) has been used in many countries as an important tool for evaluating public policies. More recently, participation of stakeholders in CBA processes has become an important issue for governments. However, CBA by itself does not provide a good environment for stakeholder participation. A major reason for this is the lack of spatial disaggregation in traditional CBA. In order to allow greater public participation, a GIS based approach is proposed. This approach uses a Geocomputational system, which incorporates soft computing theory with expert systems in a geographic information systems (GIS) environment. It is designed to generate representations of environmental, economic and social policy outcomes according to the perceptions of the stakeholders and after the CBA results have been obtained. The methodology proposed for modelling impacts in cases where uncertainty exists uses the soft computing theory of fuzzy logic to generate a raster map based on spatial inputs provided by the stakeholders involved in the decision process. This computer based system, called DISCUSS (Decision Information System for Community Understanding of Spatial Scenarios), is intended for situations where the government chooses to evaluate a policy using CBA and desires to encourage public participation in evaluating the results identified by the economic methodology. DISCUSS and the maps that it produces are being tested in a public participation case study with long-term impacts over a large area of south-eastern Australia.