When a public administration wishes to implement policies, there is a previous need of comparing different options to assess their social attractiveness. A fair policy assessment process should consider the ethical obligation of taking a plurality of social values, perspectives and interests into account; there is no doubt that Impact Assessment (IA) is then multidimensional in nature. For example, the European Commission current practice on IA considers three main objectives i.e. efficiency, effectiveness (including proportionality) and coherence and it is based on the assessment of various broad impacts such as economic, environmental and social ones. In empirical assessment of public policies and publicly provided goods, Multiple Criteria Decision Analysis is an appropriate policy tool, since it allows taking into account a wide range of assessment criteria (e.g. environmental impact, income distribution, social inclusion, and so on) and not simply profit maximization, as a private economic agent might do. This paper deals with the importance of using appropriate multi-criteria mathematical aggregation rules to guarantee consistency and transparency of results. An illustrative example dealing with a recent EC IA on modernising VAT for cross-border B2C e-Commerce is presented too. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.