Value-based argumentation for policy decision analysis: methodology and an exploratory case study of a hydroelectric project in Québec

In many countries, development projects that may have a substantial impact on the environment are submitted to a public evaluation process within which citizens use argumentation to express and justify their positions regarding a project. These justifications typically refer to various values. Subsequently, a public commission in charge of the evaluation process arrives at a conclusion. But how are the arguments of the various participants taken into account? How do values influence the commission’s recommendation? In order to arrive to an understanding of a commission’s decision process, we focus on the argumentative nature of the process and apply a methodology combining content analysis and a value-based argumentative framework. This methodology was illustrated using a case study of a hydroelectric project in Québec. First, we analysed a corpus of unstructured texts produced during public hearings and extracted the arguments and values of the participants. We then used a computational model to obtain the commission’s possible hypothetical decisions which we compared with the commission’s actual conclusion. Furthermore, we identified some preference elements of the commission, and we partially explained their attitude towards conflicting and incoherent arguments. Finally, based on our experience, we formulated some conclusions regarding the ability and promise of argumentative methods to support decision making in a participatory context.