It is only recently that PPI has been seen as a key part of healthcare practice and some form of PPI has been almost universally adopted throughout the NHS in England. However, although it is widely recognised that PPI is important by a wide range of different groups, from activists and patient groups, professional organisations to government bodies, within this broad endorsement there are a host of unresolved issues: what is the overriding justification and value base of PPI? There is also uncertainty over what the role of the PPI contributor is or should be and what such roles contribute to decision-making? This paper will consider these issues and how these, possibly, competing rationales for PPI affect the assessment PPI activities.