BACKGROUND: Patient input in HTA pathways by the appropriate disease Patient Advocacy Group (PAG) uses principally humanistic and social studies as an evidence base followed by critical evaluation against traditional  CEA (Cost Effective Analysis) via a scientific process . Patient and Public Involvement (PPI) in HTA  is associated with a low evidence base potentially limiting its value.  Research presented at ISPOR 2012 by the same authors concluded a need to improve and standardize PAG input integration in HTA decision making1 . OBJECTIVES: To investigate the way different forms of knowledge / experience are used by PAGs in NICE HTA for guideline development and new technology review.  We will look at: (i)  Influence of PAG structure, resource capability, internal process and the impact of  PAG advisory board physician representatives on scientific validation of  patient input in HTA participation. (ii)  Part I results will  inform further research into selection and ranking  criteria of social derived data compared with CEA.   METHODS: An iterative PPI best practice approach will be followed. Selection criteria: Five UK PAG groups (Neurological, Autoimmune, Rare disease, Cardiovascular and Oncology)  will be invited to participate.  The NICE PPI  Unit will nominate groups when needed. Inclusion criteria: (i) willingness to participate (ii) prior involvement in  guideline / new technology assessments (iii) presence of  medical advisory board. Research elements : Application of GRIPP criteria  (Guidance Reporting Involvement Patient Public) to ensure a  strong evidence base will guide development of an on-line survey and subsequent focus groups and interviews.  The survey, designed for SAP review, will study: size of PAG, internal process for HTA involvement, previous HTA involvement, data submitted, PAG knowledge  gaps and  involvement of medical advisory board.   Follow up by focus groups and interviews with PAG and advisory board members to identify insights/ themes.     1.      Patient Input In European HTA Systems,  ISPOR BERLIN,