2.1 Patient Involvement

Before this review, we held an online focus group with seven patient advisory group members (four women, three men) living with long-term health conditions, representing different ages, ethnicities and educational backgrounds. Specific demographics are not provided to maintain group members' privacy and anonymity. Their feedback directly shaped the scoping review questions. They highlighted the value of contributing to PPI through giving back, staying informed and connecting with peers, which informed our first question on participants' personal gains and motivations. Their discussions on how they were invited into the group showed the importance of exploring the skills required, shaping our second question. Concerns about delayed payments, lack of recognition and poor communication guided the third question on improving systems for fair treatment and effective communication. This feedback provided important context for addressing both the benefits and challenges of PPI.

2.2 Objectives

This scoping review aimed to explore the value PPI advisors and researchers derived from participating in PPI in health research. Central to this exploration is understanding relational factors, such as trust and reciprocity, and how they contribute to effective PPI. These elements can foster environments where advisors feel valued, respected and able to contribute. Three specific questions identified for this review were the following: (1) What do people get from participating in PPI? (2) Which skills/knowledge do advisors require to contribute? (3) What processes and practices ensure the meaningful involvement of advisors in health research? By framing trust, reciprocity and cohesion as central to PPI, we aim to highlight how these relational aspects underpin the broader value of involvement.

2.3 Inclusion Criteria

Published and unpublished full-text articles that explored how people with health conditions and researchers reported how they benefitted from PPI in health research through qualitative and mixed methods were included. The language was restricted to articles available in English. Full text was unavailable for 40 studies; after exploring all available access points, these were excluded from the final review to ensure data completeness and accuracy. We also excluded book chapters, reviews, editorials, opinion pieces, abstracts only and commentaries.

During the full-text screening phase, although we had planned to exclude commentaries in this review, some commentaries were written or co-authored by people with lived experience and provided useful information about their personal reflections and experiences of PPI. Therefore, these four articles were included [14-17]. Based on findings from the initial search, we updated the inclusion criteria to include commentaries to provide broader perspectives on involvement.

2.4 Search Strategy

Articles were published after 1996 to 26 October 2021 when the search was conducted. We chose 1996 as this is when PPI became formalised in the United Kingdom. We updated the search using the same databases and search terms up to September 2024 to see how PPI literature had developed.

2.5 Grey Literature

To incorporate additional sources of information to the published journal articles, we also reviewed some grey literature on PPI. The grey literature search was conducted in October 2021 and September 2024 and included targeted online searches of international government, research funders, academic and charity organisation websites (Additional File S2). We included nine policies and guidance that were relevant to the review questions (Additional File S3). Incorporating these documents helped fill gaps in the academic literature, offering insights to understand how different healthcare systems, institutions and funders frame how they value advisors and their contributions in their guidance and policies.

2.6 Data Extraction and Synthesis

We used Covidence software [21] to manage the study selection between reviewers and data extraction. Two reviewers independently reviewed the titles and abstracts (Phase 1) against the eligibility criteria, discussed any conflicts and resolved by consensus. We then independently reviewed full texts of included studies (Phase 2) and again discussed any conflict and resolved by consensus. One reviewer extracted the data (Phase 3) from the chosen studies using an adaptation of the Guidance for Reporting Involvement of Patients and the Public (GRIPP2) long form, which provides guidance on reporting involvement in research studies [22]. A sample of these studies was checked by another reviewer to validate the extracted data and codes.

2.7 Collating and Summarising Data

We used Braun and Clarke's [23] approach for thematic analysis to identify themes. We used both deductive coding based on an a priori template of codes approach [24] developed from consultation with a patient advisory group, as well as used the data-driven inductive coding approach to identify any new themes [25]. We uploaded extracted data into a Microsoft Excel spreadsheet to organise codes and look for common themes. We kept a codebook with code labels, description, source data and related themes.

3.1 Description of Studies

The search yielded a total of 3024 articles, comprising 2077 published between 1996 and 2021, and 947 published from 2021 to 2024. After the removal of duplicates and abstract screening, we assessed 256 articles and included 107 published articles and nine grey literature resources (Figure 1). The earliest article included in this review was from 2007, from 2014 onwards the literature on the topic increased dramatically, demonstrating an expanding research focus on people's experiences of participating in PPI.

Articles included a range of health conditions as well as studies that involved multiple health conditions and some with general health conditions. However, the most common health conditions were cancer and mental health, which reflects findings that most published involvement literature is in these two areas [27]. Qualitative interviews were used in 55 studies, 23 used surveys or questionnaires, 19 were commentaries or personal reflections, nine conducted focus groups and five were evaluations.

Studies were conducted across 15 different countries, including 52 in the United Kingdom, 13 in Canada, six in the United States and the Netherlands and five in Sweden and Australia, reflecting the established PPI tradition in the United Kingdom [28].

3.2 Findings

This scoping review sought to understand the value PPI advisors and researchers got from participating in PPI, the skills and knowledge required and the process and practices that facilitate effective involvement. PPI advisors were often older, of White ethnicity, highly educated with professional backgrounds. In many published articles, people brought previous personal or PPI experience to the role [29-40].

The key themes identified were (1) value from contributing to research, (2) importance of relationships, (3) attitudes and support for PPI and (4) emotional labour of involvement (Additional File S4). There were also instances where experiential knowledge was not considered equal to academic knowledge. Developing trusting relationships was essential for advisors to be treated as equal members of the research team. However, researchers found incorporating experiential knowledge into research challenging, which was affected by institutional research processes.

3.3 Grey Literature Results

Grey literature revealed that many organisations and funders lacked up-to-date, accessible information on PPI. Some web pages had not been updated in over a decade, and patient engagement frameworks were outdated, often without publication or review dates. Although organisations expressed a commitment to PPI, they provided lengthy, formal documents that were not user-friendly and offered limited guidance on how people could get involved.

Grey literature resources conceptualised value in PPI in four ways: (1) values or principles of involvement, (2) PPI as adding value to research, (3) advisors feeling valued for their contributions and (4) researchers feel their work is of value [41-44] (Henley 2020). Value was strongly related to the idea of meaningful involvement in research. Organisations offered principles to engage meaningfully with patients and the public. We have mapped these against the UK Standards for Public Involvement [45] which includes valuing contributions and building relationships in their principles and values of PPI. (Additional File S5). Notably, there was less of a focus on assessing impact. Grey literature also identified codeveloped tools to track and record how people contributed, what changes were made and why these changes matter [46, 47]. Such resources can help research teams to be transparent, have open discussions and reflect on experiences shared and their impact.

3.4 Theme 1: Value From Contributing to Research

There were different ways that PPI advisors expressed feeling valued. Some were through tangible aspects of involvement by gaining new skills and knowledge and accessing new opportunities. For example, they learned how to deliver research including data collection, data analysis, coding, co-authoring papers, dissemination and presenting at conferences [33, 48-51]. They also gained increased knowledge about their health condition, treatments and causes [36, 52-56]. Being involved in research gave advisors a sense of belonging and purpose, opportunities to meet others in similar circumstances and engage with researchers outside of a clinical setting. This was important for those who could no longer work due to their health or carer commitments [14, 33, 36, 37, 57, 58].

Payment for involvement acknowledged the economic value of advisors' time and experiences. There was an increased discussion on fair payments for involvement and non-monetary alternatives [59-61]. Although receiving compensation made some advisors feel appreciated, others volunteered without payment. Payment rates varied, often going unreported and institutional processes sometimes delayed compensation, particularly for those lacking an email, bank account or receiving state benefits (Additional File S7). Some studies noted logistical challenges and limited funding for payments [62, 63]. However, alternative methods like salaried roles [64] and honorary contracts [51] were used. Additionally, discussions around fair compensation, including paying advisors more than researchers to address socioeconomic barriers, faced resistance from ethics boards insisting on equal pay [65]. In contrast, some studies successfully paid patient partners and researchers different rates [66].

Another way to recognise efforts to research is contributing to journal articles and being included as co-authors [67]. Although advisors were listed as co-authors in just over half of the articles, it was not always clear what their contributions were, as studies were written from the researchers' perspectives. In one article, lay observers were thanked for their contributions to the paper but not listed as co-authors [34]. Only a few articles provided first-person descriptive accounts of involvement from the perspective of patients and carers. One person with dementia wrote about their firsthand experiences of being a research network member [16]. In another study, lay researchers who cared for someone with dementia shared reflections of their involvement experiences from personal diaries [32]. Whereas intrinsically valuing individuals and their experiences depended on the extent they were included in research projects. It was important for advisors to be involved in discussions, listened to and receive regular feedback and communication [15, 33, 49, 68]. They wanted to feel their contributions not only were appreciated but also had the potential to shape research and make an impact [6, 33, 64]. In one study, advisors felt valued when they used their skills and experience to deliver training [17]. In another study, researchers attending involvement meetings and contributing to meeting agendas were important [49]. For others, they valued being provided with a mentor or buddy to support them [69-71].

However, experiential knowledge was not always valued or given ‘equal status’ [72] and instead was discounted for being non-academic [58]. Clinicians could be dismissive of PPI, resulting in people feeling underused and not recognised for their skills [73]. One advisor felt the researchers talked over them, cut them off and expected advisors to agree with them [68]. People were considered problematic if they did not fit into a designated role [35] and felt undermined for not conforming to rigorous academic models [32].

3.5 Theme 2: Importance of Relationships

Several studies identified the need for nurturing and trusting relationships between researchers and PPI advisors for individuals to feel valued [17, 32, 33, 38, 39, 49, 74]. It was helpful to have informal opportunities to develop relationships and have space for discussion outside of formal meetings [75]. However, these opportunities had been reduced with meetings been held online with changes in working patterns because of Covid-19 [76-80]. Online discussions and formalities can impact relationship building such as the ability to show empathy and read body language [81].

Relationship building was important to researchers who had strong motivations and commitment towards PPI. The development of strong relationships meant that PPI advisors felt they were valued and treated as equal members of the team [16, 34, 35, 49, 54, 82] and their contributions were recognised, taken seriously and appreciated [50, 56, 71, 83]. Studies identified the importance of developing trust and rapport between advisors and researchers required time [32, 54] which enabled people to feel comfortable to discuss sensitive topics [49]. One study held meetings in lay researchers' homes to create informal safe spaces outside of the research environment [32]. In some cases, relationships developed that lasted beyond the research project [81].

Strong relationships influenced whose contributions were included as many PPI advisors were selected or approached by someone on the research or clinical team. This was due to being previous research participants, already known to researchers, or chosen based on their experience or knowledge [17, 82]. Although some researchers acknowledged that PPI relationships differed from the doctor–patient relationship [56], others continued to consider PPI advisors as patients [33]. In one study, advisors experienced negative reactions from peers who felt that they got special treatment due to their relationship with their clinician [33].

3.6 Theme 3: Attitudes and Support for PPI

Broader organisational support and attitudes towards involvement impacted how PPI was considered and delivered. For researchers to have the capacity to embed involvement into their research depended on how invested their colleagues, managers, organisation and funders were in PPI. For example, by providing researchers with support, time and resources to plan and deliver activities and meetings [15, 49, 57, 71]. Sometimes when researchers tried to incorporate experiential knowledge meaningfully, they faced criticism from funders [84] and bureaucratic recruitment processes [34]. PPI advisors with previous work experience and education felt out of their depth in meetings [33] and found presenting their own issues during patient board meetings a struggle [56]. Only one study involved interpreters during a PPI meeting [83].

The extent to which lived experience was included in research depended on funding requirements and how motivated and committed researchers were to do PPI. In several studies, researchers were unfamiliar with PPI [56, 85] often had no previous experience facilitating PPI [39] and no formal training [6]. This meant that researchers had to learn new skills not currently taught in research on how to engage and support people to take part and listen effectively [63]. There were examples of researchers and institutions thinking that PPI counted negatively towards research, impacts deadlines and harms career prospects [35, 58, 73, 86].

Several articles involved advisors in qualitative evaluation studies assessing the effectiveness of the PPI they advised on as the intervention. At times researchers facilitating the PPI also conducted evaluation of their own projects [14, 29, 48, 70, 73]. This could limit advisors' ability to be critical and honest with researchers while creating a bias towards having positive results and due to positive motivation and belief in the benefits of PPI [49, 64].

3.7 Theme 4: Emotional Labour of Involvement

This theme highlights the emotional efforts that individuals invest in sharing personal, sometimes painful experiences, building trust and navigating vulnerability in PPI. Although in some cases, people felt valued for their contributions, the act of contributing also had emotional consequences. Certain aspects of PPI negatively impacted advisors' physical and mental health due to the demands of their roles. They also had to manage periods of ill health and emotional distress from discussing their health with others. A common experience from doing PPI was fatigue [33, 55], preparing for meetings was exhausting [85], the complexities and pressures of the work were overwhelming [49] and too much time commitment [63]. In some instances, advisors could no longer continue doing PPI due to physical health needs [6], carer responsibilities [87], family commitments [31] and personal reasons [56, 57]. The views of advisors no longer involved in PPI were not available or included in the research [56].

Sharing personal experiences was draining and emotionally challenging [49, 88]. Particularly when advisors had disabling and terminal conditions, like motor neuron disease, where they would be reminded of their health and worried that other members would die [55]. With spinal cord injury, advisors feared losing hope if there were negative research results and that it would confirm there is no cure [89]. Some advisors felt ‘put on the spot’ having to share personal experiences in different situations [58]. They also expressed concern about appearing confrontational and too pernickety [30]. However, sharing experiences also allowed advisors to reframe painful memories [90], deal with their diagnosis [72] and accept their disability [91].