Beyond organisational beliefs about HTA and patient involvement, a variety of barriers to involvement need consideration to operationalise it and avoid the features of tokenism, such as lack of transparency in decision making, lack of influence, and lack of inclusivity. In 2005, Hailey identified common themes that had been reported about consumer (patient and public) involvement in health research relevant to HTA. Facey updated this table in 2017 (Chapter 5). Table 1 presents a summarised version of Hailey and Facey’s work. with some recent literature additions. Table 1 Barriers to patient participation in HTA (adapted from Hailey  and Facey ) ChallengeIssuesInteraction of patients and researchersTime needed to develop a trusting, productive relationshipResourcesAdministrative, financial, staff supportMechanisms of participationLack of a comprehensive approach that sets the goals of participation for each stage of HTA (Gauvin et al. 2015)Often chosen by the decision maker, who shapes it in a specific manner and so has control over the participation (Boivin et al. 2014)Identifying a ‘patient position’Recognising that there are differing values, expectations, environment, culture, genetics, and experience of the health system, and that it is not possible to canvass allNature and extent of patient representationDifficulty defining which patients should be involvedQuestions about representativenessConcerns about conflicts of interest and influence of health technology developersDifficulty reaching marginalised populationsTechnical demandsLack of knowledge, power, credentials or skills in scientific process and health care policy optionsTraining and educationLack of education and training developed specifically for consumersTime demands and remunerationTime commitments, working to tight timetables, payments that should be made to patientsBalancing information from researchers, the literature, and patientsLack of concordance between issues that patients regard as important and those in which research has been conductedConcern about methodology to balance qualitative and quantitative evidence and the role of costs, including questions about credibility of patient-based evidenceDevaluing patient-based evidence in evidence hierarchies (Gauvin et al. 2015)Use of patient inputUnsure what to do with patients or how to involve themConcern of tokenismImpact on timelinesPoorly moderated discussions preventing patient contribution (Facey et al. 2010) Researchers’ or clinicians’ concerns that scientific debate is softened by including patient perspectivesPossible distortion of funding decisions because of patients’ biasesSelection bias – processes may be inaccessible to many patients and ignore, or aim to eliminate bias, rather than valuing the unique perspective of individual patient participants and developing more accessible and appealing processes (Vanstone et al. 2019)Patient group concerns about how evidence from different sources is handled, weighed and valued, and that others have more influencePower differences between patients and professionals (Boivin et al. 2014) – processes value clinical and economic evidence over lived experience and patient-based evidence (Vanstone et al. 2019)Lack of awareness of HTA processesThe implications of HTA processes for healthcare systems (including beyond yes or no funding decisions) are not understoodPatients do not know how HTA is used or how to participateFew evaluations of patient inputAbsence of good quality research to show that patient involvement makes a differenceNo demonstration that patient involvement improves quality of assessmentsBurden, benefit or riskPoor consideration of the impact on patients or patient groups of involvement, including poor management of expectationsBenefit (for example, capacity building, learning, system change) should outweigh risk (for example, physical, emotional, spiritual, economic harm; Vanstone et al. 2019) Although the research reflected in table 1 was initially done in the first decade of this millennium, many of these barriers still exist. They are probably applicable not only to HTA, but also to clinical guideline development. Similarly, the variation in type and level of patient involvement in HTA identified by a European Patients’ Forum (EPF) survey in 2011 remains a feature in this field. It reflects the different rationale, motivation and approach applied in each country. The EPF confirmed that few HTA bodies and decision-making bodies involve and integrate patients’ perspectives in their reports or conduct formal evaluation of the impact of patient involvement in HTA. Moreover, when there is some form of patient involvement this is often not done in a systematic, comprehensive and meaningful way. Apart from financial resource constraints, the main challenges were perceived to be the lack of capacity, time and good methodologies to involve patients. (EPF 2013.) The first book in this field, Patient involvement in health technology assessment (Facey et al. 2017), sought to address the need for information about good methodologies and approaches to patient involvement in HTA. It drew on the expertise and experience of 80 authors from around the globe. In addition to providing case studies, the book aimed to be a cohesive guide to the field. It set out the rationale and detailed recognised approaches to participation and evaluation, and appropriate scientific methodologies for research into patients’ needs preferences and experiences. The latter included the use of qualitative evidence synthesis, discrete choice experiments (DCEs), analytical hierarchy process (AHP), patient-reported and relevant outcome measures, ethnography field work, deliberative methods, and social media analysis. Importantly, the book also sought to clarify issues that had arisen because of inconsistent terminology in the field and the resulting inappropriate use and treatment of patient involvement in HTA. Building on the work of the Health Technology Assessment international (HTAi) Patient and Citizen Involvement in HTA Interest Group (PCIG) in 2010, which described the 2 distinct but complementary approaches of patient involvement, that is, participation and robust evidence about patients’ perspectives (Facey et al. 2010), the book expanded on the different roles and considerations for each. Participation was defined as a form of dialogue for shared learning and problem solving that can aid value judgements throughout the HTA process. Described as a mosaic of approaches selected according to the goal(s), participation is often sought to address gaps and uncertainty in the evidence and recognised for its role in interpreting evidence for real-world implementation. It commonly takes the form of patient input, such as written submissions and committee membership, which is characterised by its source (patients and patient groups gathering and presenting information to aid decision making). Whereas evidence about patients’ perspectives, known as patient-based evidence, is intended to provide evidence of patients’ needs, preferences and experiences in a form that can be critically assessed, as are other forms of scientific evidence. Table 2, by Staniszewska and Werkӧ (2017), summarises key differences between the 2 approaches. Table 2 Summary of the differences between patient-based evidence and input from patient participation in the HTA process (Staniszewska and Werkӧ 2017) Patient-based evidencePatient participation in the HTA processProduced through research, generally published in peer-reviewed journalsOriginates in perspectives of individuals, groups of patients or organisationsDraws on a range of methodologiesDoes not necessarily use or need a specific methodologyDraws on robust scientific methods whose strengths and limitations are known, and provides a robust conclusion that can be clearly interpretedThe quality of the methods used to gather inputs may be unclear or not considered as importantDepends on appraisal of quality, including formal critical assessment and peer reviewThe concept of quality may depend on factors such as authenticity or diversity of perspectivesResearch is based on research genres and specific research questions, and takes time to generate from either primary or secondary researchPatient participation can be used at any point in the HTA process, and may be in the form of a dialogue to enable immediate reaction to an emerging issueMay be more limited in accounting for context of the HTA, depending on whether studies have considered contextCan consider the context of the HTA questionCan be based on a synthesis of studies, which means a comprehensive, unbiased view of a patient issue can be summarised very effectivelyProvides a selection of perspectives that may not be comprehensive but are informativeResearch directly addresses questions of bias and balance, which provides some assurance of qualityBias in relation to patient input is a complex concept that requires exploration in the future In addition to clarifying these distinctions and describing appropriate methodologies and approaches, Facey at al. (2017) drew on the work of Abelson et al. (2016) and the OHTAC Public Engagement Subcommittee (2015) to suggest that patient involvement begins with defining the goals for involvement, which should then guide decisions about approaches, methods and evaluation within the framework of the HTAi Values and Quality Standards for Patient Involvement in HTAi (see the section on HTAi Values and Quality Standards for Patient Involvement in HTA for more information). These goals may be instrumental, democratic, scientific or developmental (OHTAC Public Engagement Subcommittee 2015). The editors and many of the authors of the book were active members of the HTAi PCIG. This interdisciplinary group, formed in 2005, promotes awareness of patient and citizen involvement, encourages methodological development, shares best practice, and supports jurisdictions seeking to introduce or develop involvement. PCIG has been active in developing tools for HTA bodies and patient groups to adapt for local involvement activities. Some of these tools may be suitable for adaptation for clinical guideline development. Key tools are described in the next section and further tools can be found on PCIG’s web pages.