Using Argumentation to Structure E-Participation in Policy Making Trevor Bench-Capon A , Katie Atkinson A , and Adam Wyner B A: Department of Computer Science, University of Liverpool, Liverpool, England B: Department of Computing Science, The University of Aberdeen, Aberdeen, Scotland Abstract. Tools for e-participation are becoming increasingly impor- tant. In this paper we argue that existing tools exhibit a number of limitations, and that these can be addressed by basing tools on devel- opments in the field of computational argumentation. After discussing the limitations, we present an argumentation scheme which can be used to justify policy proposals, and a way of modelling the domain so that arguments using this scheme and attacks upon them can be automat- ically generated. We then present two prototype tools: one to present justifications and receive criticism, and the other to elicit justifications of user-proposed policies and critique them. We use a running example of a genuine policy debate to illustrate the various aspects. Keywords: e-participation, argumentation, dialogues, deliberation, values, pol- icy making. 1 Introduction An important feature of democracies is that citizens can engage their govern- ments in dialogues about policies. Traditionally this was done by writing letters: government departments employed a large number of people whose main func- tion was to reply to these letters on behalf on the Ministers to whom the letters were addressed 1 . Although a large number of letters concerned the particular individual circumstances of the writer, others were directed towards general pol- icy matters. Such letters tended to fall into one of three types: some were in pursuit of information and sought a justification of some policy or action; some (probably the most common) objected to all or some aspects of a policy; a third type made policy proposals of their own. The policies we have in mind have a very broad range, running from particular local issues with a small impact to issues of national importance which potentially impact on all citizens. In this introduction we will characterise each of the three different types of engagement and illustrate them with reference to a simple motivating example concerning a 1 The first author worked as a Civil Servant for the UK Department of Health and Social Security in the late seventies, and part of his duties was replying to such correspondence.