Building a Shared Model for Multi-criteria Group Decision Making - Experience from a Case Study for Sustainable Transportation Planning in Quebec City

Shared procedures to build a consensus within a group decision process are sometimes used in multi-criteria decision-making. Facilitators often face several challenges and the solutions to overcome them are scarce and not well documented. This paper presents a case study within a decision framework that combines problem structuring with the multi-criteria decision aid method MACBETH in order to build a shared preference model. The framework was applied in a transportation planning context with a group of professionals from Quebec City, Canada to assess and rank streets as a function of their potential to become Complete Streets. The analysis of the process showed that difficulties in expressing preferences, access to data during workshops, group size, group discussion management, and project length were encountered. Nonetheless, the proposed framework and the use of sub-groups to build criteria scales were a way to overcome these challenges and allowed us to successfully complete the project.