assessing institutional feasibility and political viability of strategic trajectories1.

The paper discusses a simple methodological tool for supporting the participatory elaboration of future urban scenarios through successive approximations. It systematizes one possible way to build answers to a set of critical questions when attempting to compose strategic urban programs. To this end, we focused on devising a simple sequence of understandable, easy-to-apply Multi Criteria Evaluation instruments which- by means of ‘light ’ ‘accounting ’ calculation procedures- may “help (planners) to think ” (Calcagno, 1972). The deliberate simplicity of this approach- an ‘intelligent’, transparent and intentional management of elements of analytical and intervention fields, funded on their exhaustive qualitative descriptions and on explicit statements of interests and purposes- prioritises the political side of decision – making. Thus, the paper also seeks to contribute to the reflection on the roles and views of social actors when defining and constructing urban public scenarios. First, we discuss the conceptual and political contents and implications of Diagnoses and Scenario-building, in which involved actors (i) elaborate causal interpretations of urban processes, (ii) specify and select strategic trajectories and (iii) compose and structure project portfolios, by (eventually) supporting them through progressive agreements and consensus. Next, we propose a methodological approach t