The technique of diagramming arguments was used since the second half of
the last century by modern theorists of argumentation such as Wigmore, Toulmin and
Beardsley, with theoretical as well as didactic aims. Today, a number of software
applications (Argument Diagramming tools) are devoted to support the production of
arguments, their analysis and evaluation. Their effectiveness is usually assessed
considering the impact they have on people’s acquisition or reinforcement of critical
thinking skills. This chapter aims at suggesting criteria to design and evaluate Argument
Diagramming tools from the point of view of argumentation theory. Two types of
criteria are presented: interaction-related criteria, which are based on the conception of
argumentation as a communicative interaction; and argumentation-related criteria,
which derive from the very features of argumentation as a specific kind of reasoning.
Keywords: Argumentation theory, argument diagramming tools, evaluation,
design, argument scheme, argumentation structure.