|It has been widely recognised within academic and policy circles that deliberation of science-based issues and formulation of policy is no longer the exclusive realm of politicians and experts. In order to develop robust, transparent and effective policies new participatory structures for involving a wide range of actors and the public are urgently required. The PATH project will form a network bringing together academics, practitioners, policy-makers and stakeholders to exchange knowledge and develop future directions for the involvement of society in the deliberation of science-based policy issues.The project will focus specifically on two persistent challenges: scale and epresentation. To date, participatory processes have largely been used at a local scale. However, many policy challenges are relevant to a regional or international scale and hence guidance on how participatory processes can be scaled-up is a pertinent issue. Of key concern in such processes is how best to represent a diverse and diffuse public as well as 'silent voices' (e.g. children, future generations). These two cross-cutting themes of representation and scale will be explored at a generic level, and via three case study areas, namely:genetically modified organisms (GMOs) in agriculture, biodiversity conservation and nanotechnology. Information exchange and development of innovative future directions will be achieved through an international workshop focusing on issues of representation and scale, and an international conference which aims to integrate elements of best practice in science-based policy deliberation and sketch out future directions with regard to the three case study areas. Project outcomes will be disseminated to academic and non-academic audiences through policy briefs, conference proceedings, journal articles, reports and the project website.