Modelling expertise: Experts and expertise in the implementation of the Water Framework Directive in the Netherlands

The thesis deals with the use of computer software to inform policy planners in the context of debates about evidence based policy making and the role of experts and expertise in policy planning. Specifically it analyses the implementation of the European Water Framework Directive (WFD) in the Netherlands and the development of a decision support system that was explicitly intended to be used by policy planners in the process of developing the programmes of measures to reach the WFD objectives. Through detailed analyses of both processes it shows how the WFD implementation process and the development of the instrument mutually influenced each other in ways that make the two domains hard to untangle. This is contrary to the ideal of evidence-based policy planning ideal that requires two separate domains with the policy domain asking questions, while the expertise domain only provides answers. Actor-Network Theory was applied to show the entanglement and to develop the roles of both human and non-human actors.