The need of making decisions pervades every field of human
activity. Several decision support methods and software tools are available in
the literature, relying upon different modelling assumptions and often
producing different results. In this paper we investigate the relationships
between two such approaches: the recently introduced QuAD
frameworks, based on the IBIS model and quantitative argumentation, and the
decision matrix method, widely adopted in engineering. In addition, we describe
Arg&Dec (standing for Argue & Decide), a prototype
web application for collaborative decision-making, encompassing the two
methodologies and assisting their comparison through automated transformation.