Over the last decade, processes of public engagement – in which members of diverse publics express their views, concerns and recommendations – have become increasingly common features of STI policy. There are multiple rationales for public engagement in STI policy. First, public engagement can broaden the knowledge base on which to make STI policy decisions, enhancing the quality and relevance of the knowledge produced and helping to steer science and innovation toward socially desirable objectives. Second, engaging the public upfront on questions of controversial technology policy may stave off a public outcry and enhance trust between scientists and the lay public. Third, from the perspective of democratic governance, public engagement can enhance the meaningful participation of citizens in decisions that affect them deeply (Fiorino, 1990; Stirling, 2008). But public engagement can also help improve the relations of science and society by building a more scientifically literate, supportive and engaged citizenry.