How do we best engage young people in decision-making about their health? A scoping review of deliberative priority setting methods

Introduction International organisations have called to increase young people’s involvement in healthcare and health policy development. We currently lack effective methods for facilitating meaningful engagement by young people in health-related decision-making. The purpose of this scoping review is to identify deliberative priority setting methods and explore the effectiveness of these in engaging young people in healthcare and health policy decision-making. Methods Seven databases were searched systematically, using MeSH and free text terms, for articles published in English before July 2021 that described the use of deliberative priority setting methods for health decision-making with young people. All titles, abstracts and full-text papers were screened by a team of six independent reviewers between them. Data extraction followed the Centre for Reviews and Dissemination guidelines. The results are presented as a narrative synthesis, structured around four components for evaluating deliberative processes: 1) representation and inclusion of diverse participants, 2) the way the process is run including levels and timing of participant engagement, 3) the quality of the information provided to participants and 4) resulting outcomes and decisions. Findings The search yielded 9 reviews and 21 studies. The more engaging deliberative priority setting tools involved young people-led committees, mixed methods for identifying and prioritising issues and digital data collection and communication tools. Long-term and frequent contact with young people to build trust underpinned the success of some of the tools, as did offering incentives for taking part and skills development using creative methods. The review also suggests that successful priority setting processes with young people involve consideration of power dynamics, since young people’s decisions are likely to be made together with family members, health professionals and academics. Discussion Young people’s engagement in decision-making about their health is best achieved through investing time in building strong relationships and ensuring young people are appropriately rewarded for their time and contribution. If young people are to be instrumental in improving their health and architects of their own futures, decision-making processes need to respect young people’s autonomy and agency. Our review suggests that methods of power-sharing with young people do exist but that they have yet to be adopted by organisations and global institutions setting global health policy. Supplementary Information The online version contains supplementary material available at 10.1186/s12939-022-01794-2.


Introduction
Organisations including the World Health Organisation (WHO), the United Nations International Children's Emergency Fund (UNICEF), the Wellcome Trust and the Lancet recognise the importance of engaging young people in decision-making about their health [1]. The COVID-19 pandemic has had disproportionate impact on the lives and health of young people around the world [2]. The WHO-UNICEF-Lancet Commission on 'a future for the world's children?' has launched a call for involvement of young people in all decision-making policies and coalitions [3,4].
Young people make up approximately a quarter of the world's population [5,6]. Investing in young people's health has the "triple benefit" of improving their current health, their health as adults and the health of their children [7]. Adolescence is a critical period of the lifecourse, during which young people undergo the physical and psychological transitions that accompany pubertal growth in early adolescence (10-14 years), brain maturation, and social and emotional development in later adolescence (15-19 years) [8]. They start to gain autonomy over life decisions, depending less on their parents and becoming more susceptible to the influence of their peers. They make important health and social choices that often persist into adulthood [9][10][11]. These powerful physical and psychological changes represent a unique phase between childhood and adulthood, which requires specific consideration and services. The Association of Young People's Health emphasise the need to conceptualise how health inequalities arise in young people, which they position as underpinned by the young person's economic inequality which shapes their social determinants [12]. This leads to variability in how the young people access and experience services and support, their health behaviours and relationships with parents, carers and peers. This will ultimately shape their physical and mental health [12].
Over 30 years ago, the United Nations Convention on the Rights of the Child determined the right of young people to make their own life decisions, taking into account their age and maturity [13]. In her annual report for 2021, the UN youth envoy urges international organisations and institutions to acknowledge this commitment and to make decisions based on working with and listening to young people in a meaningful way [14]. Tools such as those developed by Save the Children and Women Deliver are excellent means of supporting young people to develop skills in advocacy [15,16]. We still lack, however, effective methods for facilitating meaningful engagement of young people in setting priorities for health policy and healthcare decisions that affect their lives, livelihoods and futures.
There are a number of recognised priority setting techniques used most commonly with adults [17]. These tend to be categorised by two levels of engagement. The first is a non-deliberative approach which consults members of the public about their priorities, final decisions about which are made by those running the process [18][19][20][21][22][23][24][25]. Focus groups and interviews tend not to facilitate discussions about trade-offs in decision-making, such that having more of one option potentially results in having less of another, which is a key feature in priority setting [17]. The second is a deliberative approach which engages members of the public in a two-way dialogue and results in a set of priorities agreed with healthcare providers, policy makers and health researchers. Deliberative approaches have value over non-deliberative as they involve a process that brings together different points of view to derive a consensus without coercion, deception or manipulation [26]. This is both a more equitable and respectful way to involve the public in health policy and healthcare decisions and is likely to create more effective health services as they deliver what people prioritise. Deliberations also facilitate discussions about trade-offs and expectations when setting priorities.
Manafo and colleagues conducted a scoping review of public and patient priority setting, and identified five successful deliberative methods [17]: James Lind Alliance Priority Setting partnership (United Kingdom) [14], Dialogue methods (Netherlands) [16], Deep Inclusion (United States) [17], Choosing All Together (United States) [18], and Global Evidence Mapping (Australia and New Zealand) [27]. To date, these deliberative methods have rarely been used with young people to engage them in setting priorities for their health care. It has been more usual to use non-deliberative methods in consultations with young people [28][29][30][31][32][33][34][35][36]. The purpose of this scoping review is to identify and evaluate deliberative priority setting methods that have been used to engage young people in healthcare and health policy decisions.
1. Which deliberative methods have been used to engage young people in healthcare and health policy priority setting? 2. What features of these methods make them effective in engaging young people with healthcare and health policy priority setting?

Study selection
A scoping review was conducted in order to identify and evaluate deliberative priority setting tools that have been used to engage young people with healthcare and health policy decisions. This review method was chosen in order to produce a rapid account of the extent, range and nature of key tools [37]. We searched Prospero for existing reviews of priority setting in healthcare with young people, and as none were found we progressed with designing the scoping review strategy. The initial search was conducted in May 2019 and included major medical and social science databases including Cochrane library, Embase, MEDLINE, psychINFO, web of science, and CINAHL. There was no restriction on the publication date, and a complete search strategy can be found in Additional file 1. The search was updated in July 2021. The search strategy was narrow in order to focus on priority setting in healthcare with young people in particular. We engaged via meetings and emails with UNICEF experts and academic experts in adolescent health and priority setting known to the research team, to identify papers missing from the database search. Papers were stored using Endnote version X9 and duplicates were removed. The papers were then screened using the Rayyan QCRI app and website [38]. All titles and abstracts were screened by one reviewer, and a second reviewer from the review team screened 10%. The full-text of relevant papers was obtained and assessed against the inclusion criteria (see Table 1). Studies were included that used a mixed-methods design including literature reviews, qualitative and quantitative methods, involved young people aged 10-24 years [39] and were based on priority setting to determine healthcare decisions. Bibliographies of retrieved papers were searched and experts in young people priority setting identified an additional paper. Healthcare decisions encompassed both medical and dental decisions. Exclusion of papers that did not meet the inclusion criteria was agreed by the review team.

Data analysis
Papers were screened using the following definition of deliberative priority setting: 1. Research planning included gathering and analysing identified research priorities by engaging patients and the public along with clinicians and researchers. 2. Followed by prioritization of topics through dialogue between all stakeholders [26] To focus the data analysis, we used Abelson et al's four components for evaluating deliberative processes: 1) representation, referring to geographic, demographic or political inclusion of young people; 2) the structure of the process or procedures, emphasising the timing of public engagement in decision-making processes, the level of engagement, and opportunity to share views and gain mutual respect; 3) the quality of information given to participants in terms of how it is selected, presented and interpreted for them; and 4) the outcomes and decisions arising from the process, in terms of achievement of consensus, participant satisfaction, and legitimacy and accountability (see Fig. 1) [40]. As the current review aims to identify and describe different types of deliberative methods that have been used to engage young people, we first outline the features of each deliberative priority setting tool before evaluating them using Abelson's evaluation criteria. Observational studies.

Population
Any population/group of a young people, age between 10 and 24 years.
Children below age of 10 years. Adult populations above age 24 years.
Intervention Interventions explicitly using deliberative priority setting methods.
Interventions using non-deliberative priority setting methods such as solely focus groups, interviews and surveys.

Outcome
Decision-making and achievement of consensus by young peoples.
Decision-making and achievement of consensus solely by parents, caregivers, health professionals, educators, or other adult stakeholders.

Data synthesis
A summary table was produced (Table 2) which describes the characteristics of the identified studies including study design, priority setting features, setting and participants, assessment measures and conclusions. The summary table was used as the basis of a narrative synthesis of data examining and evaluating the types and effectiveness of deliberative priority setting techniques used to engage young people with healthcare and health policy decisions. Assessing the quality of included studies is unnecessary in a scoping review because it allows for a greater range of study designs and methodologies than a systematic review [37].

Results
A total of 9 reviews and 21 primary studies were identified that used a deliberative priority setting method with young people (Fig. 2). The deliberative priority setting methods were similar in that they all attempted to engage young people in a two-way dialogue with researchers, policymakers, health professionals and parents among others. Table 2 describes the range of deliberative priority setting methods and indicates differences between the methods in the frequency with which and length of time over they engaged young people, the data collection tools that they employed and with whom they engaged.

Geographic representation
Studies reviewed tended to be conducted in highincome countries (i.e. Australia, Canada, Japan, the Netherlands, United Kingdom, United States), and covered rural and urban areas but this distinction was not clearly reported in most studies. Two additional studies were conducted in rural communities in middle income countries (i.e. South Africa and Tanzania) [39,71]. One study included participants from three different countries: New Zealand, Fiji and Tonga [65]. The experience of young people from low-and-middle-income countries was under-represented in papers reviewed. Studies tended not to report the different geographical regions within the countries from which young people came. One study held online stakeholder meetings which allowed for inclusion of a wider geographical spread of participants but only those with access to the appropriate technology [64].

Demographic representation
Studies included young people of different ages up to 25 years. The majority of studies worked with combined groups of children and young people; some studies grouped together all children and young people under the age of 18. This made it difficult to draw conclusions about the specific experiences of adolescents,  All studies were conducted in the United States.
The priority setting techniques included decision coaching, coaching plus educational aid, and education alone. • Five studies in six papers were identified.
• Lack of interventions focused on supporting young people's decision making.
• Studies included evaluation of parent and child decision but did not discuss children's capacity to make their own decisions.    The discrete-choice experiment survey included 27 attributes on service delivery and treatment outcome. • In the pre-testing interviews, young people found that the survey difficult to understand and so the survey was modified to increase acceptability.
• Pre-testing interviews suggest that the survey encourages decision preference for treatment.
• Including young people in the all stages of survey development improved acceptability.  Qualitative study with peer researchers Step 1: Working with Peer researchers to identify participant Step 2: Setting up focus groups with peer researchers.
Step 3: Converting evidence synthesis to user friendly infographics with peer researchers Step 4:Allow young people to engage with the material.
Step 5: Identify their own priority subjects though interactive activities Step 6: Involvement of young mothers to organise the themes Pregnant and parenting young women under 23 years and their services providers in Canada.
Better Outcomes Registry Network (BORN), focus group Discussions and first -second order themes with contribution from participants • Important to combine evidence-based synthesis and local context specific knowledge or understanding.
• It was important to the young women to choose how their experiences are ordered.
• Confidentiality was respected if the young women choose not to publicize their story.  • However, it also shows that long-term and meaningful participation requires an organizational shift that moves from an adult-led agenda towards a youth-led agenda.
• There is a need for an organizational climate in which unsolicited advice is valued and facilitated by formal structures to prevent adolescent patients' frustration and demotivation in the longer term. 17 Guinaudie et al. 2020 [57] Insights from the co-design and implementation of SDM in knowledge translation, clinical, operational, and research strategies within the ACCESS OM network.
Lived mental health experience is acknowledged and integrated as unique experiential knowledge and unique expertise to advise and to guide the project in collaboration with researchers, mental health clinicians, and decision makers.    (7), academics (8) and commissioner (3). Web based study to include diverse stakeholders from different locations.

ACCESS Open Minds (ACCESS
Web based Delphi survey developed to critique the reach, equality, feasibility, effectiveness, acceptability, and cost of school based physical activity interventions.
This was conducted in two rounds, and showed increase consensus with the majority. • Participants ranked mental health and wellbeing as the most important to consider, followed by enjoying school.
• Making the intervention effective was consistently ranked the most important in each round.   Follow ups, where clients were asked if they were able to make decisions before and after decisions aid. Clinicians rated how satisfied they were with decisionmaking. • After the decisions aid, young people were more able to make a decision, and had significantly reduced depression scores.
• Potential for young person's collaboration in the decisionmaking process of their treatment.
• Clinicians supported the decision-making choices.  The Delphi approach conducted over three rounds enabled voting of health priorities and reducing the priorities from a list of 10 in the first round to five priorities in the second and third rounds.
In the workshops, face-to-face and participatory visualisation facilitated deliberation between stakeholders and researchers. • There was consensus from stakeholder and researchers that peer pressure and lack of information were underlying causes of adolescent health problems.
• The stakeholder forum formed in workshop three worked well with the researchers throughout to further develop public engagement strategies, share preliminary findings, discuss research progress,and identify policy champions to act on research findings. 28   which given their developmental stage, are likely to have been significantly different to those of younger children. Very few studies described the ethnic origin of participants [54] and no studies reported the socio-economic status of the young people involved. The major criterion for selection of participants in the studies reviewed was that they were receiving healthcare for a chronic or critical condition. These conditions included mental illness, cancer, obesity, neurological conditions and HIV. Adults were almost always included in addition to the young people in the decision-making processes described in these studies. This appears to have been necessary to give credibility to the studies' conclusions.
A study in Tanzania involved community groups and local cultural experts in key informant interviews in order to address the local perception that it was not sufficient simply to base decisions on the views of young people [39]. Leaders in this community also provided the research team with their opinion about how best to recruit young people to priority setting deliberations and suggested suitable data collection sites and methods [39]. In a South African study, community leaders, youth organisations and research unit community advisory groups were included in the deliberative process to facilitate the translation of study findings into changes in practice but also to provide a more direct link to policy makers beyond the end of the project [67].

Political inclusion
The influence of politics in setting health priorities was rarely discussed in the studies reviewed. One exception was the study in South Africa which involved representation from the African National Congress (ANC) Youth League in recognition of the role that politics and politicians play in setting health priorities for young people [67].

Structure of deliberative processes and procedures
The studies reported using a range of techniques to engage young people in deliberation about priorities in healthcare and health policy. Five studies created a young people's committee or council, where young people worked together with stakeholders from hospitals and mental health services, making decisions to enhance young people's satisfaction, influence hospital strategy, and to empower young people with chronic illnesses [49,53,56,57,62]. The authors of these studies concluded that health professionals should engage with young people over an extended period of time to build meaningful relationships. They also recommended using incentives and offering training in skills such as advocacy to increase engagement of young people. Three studies facilitated conferences, panels or stakeholder meetings with young people and researchers [53,54,63]. Six of the reviews identified described studies that employed methods to improve engagement, including education, coaching, and therapeutic techniques to engage their emotions, prevent emotional isolation and help build trusting relationships [45-47, 49, 57, 72]. One study also included siblings in the 'Teen Advisory Board Committee' , which was found to deepen and enrich the decision making experience as young people could discuss the decisions with someone they trusted and who was closer in age than a parent [63].
One study that used vignettes to create stories around treatment decision making in a paediatric oncology setting, found that young people and parents preferred to be given information simultaneously [60]. Another used photovoice and storytelling to explore sexual and mental health priorities [39].

Digital interventions
Various digital methods were found to be successful in engaging young people in making decisions about their healthcare and health policy. Online decision aids for young people with depression, often used in consultations, created a confidential environment for sensitive issues [60], and also increased accessibility for populations such as those who were physically disabled, lived in remote areas or were without transport. Stakeholder webinars were considered a successful way to engage young people across locations [54]. Younger people found webinars more user friendly than parents, who described accessing the webinars as requiring a 'generational learning curve' . Different digital media were employed such as video, photographs and a "Decision Slider", which allowed young people to record their decisions multiple times [45]. Digital methods were also used to recruit young people to deliberations using social media (Facebook) support groups [56]. One research team incorporated face-to-face engagement throughout the deliberation cycle, as past research has found that a combination of face-to-face and digital interactions is most effective [62]. This is, of course, only possible for communities of young people with access to digital technology.

Timing of public engagement in decision-making, levels of engagement and opportunities to share and foster mutual respect
Deliberative priority setting methods varied in duration and contact time with young people, ranging from one off meetings to years of engagement, and from face to face to web-based interactions. Studies with organised panels and committees had longer duration and more contact with young people and stakeholders than survey approaches and was felt by young people to be a more respectful and meaningful way to work. Committees sometimes maintained young people's engagement for months [56,57,62]; Coad et al's "youth council" ran for 18 months [49] and Rich et al. reported that their "Teen Advisory Committee" ran monthly from 2002 until publication in 2014 [53]. Panels tended to maintain contact over a shorter period; the workshop using the ANGELO framework for obesity prevention, for example, which was delivered over 2 days [63], or in 18 webinars [54]. Surveys were more likely to be conducted in a single interaction, the online decision aid for youth depression is one example which was used in a single 50-minute appointment [60]. Similarly, one online Delphi survey was conducted at two time points each consultation lasting 30 minutes [62]. Studies that included young people in all stages of the decision-making and prioritisation process were felt to provide the maximum opportunity and respect for the contributions of young people. This included respecting the anonymity of the young people's stories [55], giving a young people's council the opportunity to provide ongoing insights for an acute hospital trust and involving them extensively in the evaluation of impact and in publication of papers [49]. Most studies did not say if young people were given the opportunity to challenge the decision making process, which Abelson considers important as an indicator of mutual respect [40]. Three studies commented on the power imbalance between young people and researchers or parents in the deliberative process [57,58,72]; specifically they observed that the research team's decisions were given more significance than the young people's. The result of these power imbalances was to systematically exclude young people from the decision-making process, thus disempowering young people from a process that was intended to empower them [60]. To address this, Guinaudie et al. 2020 created separate and shared spaces for young people and family members to consult with each other early in the project and to develop clear messages before contributing to larger multi-stakeholder discussions with research teams [57]. In some studies, young people were given the opportunity to reflect on and feedback about any difficulties they had in making their views heard. In a South African study, young people were given the opportunity to develop strategy for public engagement, research progress and to become champions of the strategies and decisions made following the workshops, communicating how much the researchers valued the young people's contributions [67]. One study reflected on the power of social desirability and the way young people's expression was promoted or impeded by the presence of other young people, healthcare professionals, parents and other adults which in turn shapes young people's decision-making [39]. Studies suggested that future research should focus on developing young people's capacity for decision making and by respecting and taking into consideration their preferences, values, and emotions [49,62]. Such development occurs through acknowledging young people's experience of the interactions they have with healthcare professionals or their parents, the power differential between them and the impact of these interactions in promoting or impeding their agency [39,49,57,58].

Quality of information given to participants
Studies presented a number of methods to inform selection of priorities to be considered in the process, including literature reviews [41,46,54], qualitative data from experts in the field [60,63,67] or from young people [45]. It was unclear from these studies whether literature reviews or qualitative data were more useful in informing priority selections [44,49]. In order to ensure no potential priorities were missed, some studies used both qualitative research and literature reviews to identify lists of options for change to healthcare and health policy for young people [45,50,56,60,62]. In order to select from these potential priorities, studies described using methods such as decision aids for young people with diabetes [72] and depression [60], discrete-choice experiments for patients with hypodontia [56], and Delphi studies for identifying physical activity priorities [62] and young people's general health issues in South Africa [67]. Involving young people in the design of these methods improved their acceptability [67]. Decision aids and shared decision-making toolkits aided the delivery of high-quality information to young people, health professionals and parents, which decreased decision conflict and positively impacted on the treatment adherence for young people with chronic conditions [47,51].
Visual methods were useful in aiding young people's decision-making. One study used vignettes with pictures and stories, which were found to be especially effective for communicating about sensitive issues such as childhood cancers [60]. Jordan et al. (2019) used 'life grids' to explore important events in the lives of young people with long term health conditions and their interactions with doctors, and then used pie charts to explore discrepancies between the role that the young people wanted in healthcare decisions and how interactions with doctors affected their ability to take part in decision-making [58].

Outcomes and decisions
Abelson identifies three important types of outcome against which the deliberative process can be evaluated: 1) achievement of consensus, 2) participant satisfaction, and 3) legitimacy and accountability [40].

Achievement of consensus
Reaching consensus was an important goal for all types of deliberative processes whatever route to decision making was taken because it was required to deliver decisions on the healthcare and health policy priorities to be addressed [54,[63][64][65]. Some studies actively managed the process of reaching consensus through use of Delphi methods, where a panel of experts is asked in a series of consultations to select from a pre-defined list of priorities, their responses are aggregated and shared after each round until consensus is reached [67,73]. Lopez-Vargas et al. 2019, who conducted a one-day workshop with children with a chronic condition asked each participant to generate a research questions that was important to them, and each question, of which there were 78, was then ranked in terms of importance by the group, which generated the top three questions to be explored in more depth [59]. Surveys of other types were also used to reduce decision conflict and generate consensus [52,61,66].

Participant satisfaction
Deliberative processes that were more genuinely inclusive of their opinions were felt by young people to be more satisfactory [39]. Studies which generated greater participant satisfaction were those of longer duration and more frequent contact [54,63], panel discussions which gave young people confidence to speak out [65] and skills in leadership [60,62], and those that included young people in all stages of the priority setting process including designing the decision making tool [52,53]. Participant satisfaction was also greater when they perceived that the decisions they made were for wider benefit and provided better health outcomes for others than themselves [62]. One systematic review and meta-analysis found that, although shared decision making techniques such as workshops, information sheets, videos and websites significantly improved knowledge of disease and reduced decision conflict, they did not improve patient satisfaction [48].

Legitimacy and accountability
Studies were more or less legitimate depending on the degree to which young people's input was incorporated into final decisions made by health care managers and policy makers. One positive example of this were two studies where a hospital trust reported on the outputs of young people's committees which included advisory roles and creating patient information and explained the direct impact of these outputs on hospital strategy [54,63]. Three reviews identified found that some studies excluded young people from the final decision-making process, and the young people's capacity to prioritise was largely ignored [42,43,48]. Contrastingly, three studies encouraged young people to make final decisions on health-related matters; these were focused on hospital strategy, mental health and obesity prevention [54,65,66]. Issues with the power dynamic between researchers, parents and young people were also reported in some studies [54]. Legitimate participation of young people in decision making clearly requires a move from an adultled agenda towards a youth-led agenda [56]. Accountability in terms of how young people's input into decision making influenced outcomes was rarely discussed. An unusual example is described in a study in South Africa where a community forum was held following the priority setting process, which aimed to communicate to community leaders and disseminate widely young people's health priorities [67]. Despite most studies reviewed suggesting that involving young people in decision making could improve intervention design and add value to healthcare systems, none described how this process influenced healthcare delivery.

Discussion
This scoping review identified 9 reviews and 21 studies that described the use of deliberative priority setting techniques in engaging young people with healthcare and health policy decisions. Studies in this review were mainly conducted in high-income countries, included young people and adults together in shared decisionmaking and rarely reported participants' demographic status.
Which deliberative methods have been used to engage young people in healthcare and health policy priority setting?
A number of different deliberative priority setting methods have been specifically developed for use with young people including the James Lind priority setting tool and ANGELO framework, setting priorities with committees, councils, community groups and conference panels, using surveys such as decision aids, Delphi methods, and creative methods like vignettes, photovoice and life grids. The deliberative priority setting methods were similar in that they all attempted to engage young people in a twoway dialog with researchers, policymakers, health professionals and parents among others.
Very few of the studies describing development of deliberative priority setting methods for young people make reference to the priority setting methods that are frequently used with adults [17]. Such methods used with adults include Dialogue methods (Netherlands) [16], Deep Inclusion (United States) [17], Choosing All Together (United States) [18], and Global Evidence Mapping (Australia and New Zealand) [27]. One exception of a priority setting method that was developed for adults but has been used with young people is the James Lind priority setting tool [14]. Manafo et al. (2018), however, described all this list of methods developed for adults to be inclusive, objective, and specific to the priorities of stakeholders involved [17]. It follows that there may be features of these methods that could successfully engage young people in developing a sense of autonomy and perceived control over their health, facilitating their capacity to be effective adult health users [9][10][11].
What features of these methods make them effective in engaging young people with healthcare and health policy priority setting?
Abelson's criteria were used for evaluating deliberative processes and their success in engaging young people [40]. Respectful and inclusive priority setting processes were those that involved young people in all stages of the process, including in designing the study, worked with young people for an extended period of at least a year, used digital methods together with face to face to determine priorities and took steps to address power differentials from the start of the project. Combining evidence from literature reviews with qualitative exploration with young people, parents and researchers was found to generate the fullest list of priorities for presentation to the young people and other stakeholders. Delphi methods were seen as particularly useful tools for ranking priorities and creative methods such as using vignettes improved young people's understanding of topics under consideration. All studies reported that consensus was reached between participants, but the extent to which the young people made the final decisions, and therefore the legitimacy of the studies, was greater in some studies than in others. The deliberative priority setting processes varied from a single 30-60-minute commitment from the young people, to meeting monthly over many years. Ongoing contact with young people is described as one of the key principles of the engagement process [74]. There are specific issues with involving young people in the long term that need to be considered. This was highlighted in one study that found challenges with scheduling webinars as young people transitioned over study courses or between high-school, college or full time employment [64], emphasising the need to monitor changes in circumstance and commitments of the young people if their involvement is to be sustained. Providing appropriate training and support is also important for maintaining young people's commitment [75]. These authors identified that engaging young people over time strengthened the trust and respect between young people, health professionals and researchers, and increased young people' ability to make a meaningful contribution. Issues of funding and sustaining young people's long-term involvement were somewhat surprisingly not raised by these studies. Somewhat surprisingly young people appeared to have no issues with the quality of information provided to support the priority setting activities. Fishkin's work on deliberative democracy suggests that this is a key factor in the success of deliberative processes [76]. One of the ways in which studies addressed this issue was to train young people to facilitate youth councils [49,63]. These young facilitators were seen as credible sources of information for other young people involved in the process.
The undermining effects of power imbalances between different types of participants on young people's autonomy was raised in multiple studies [39,49,57,58,64,72]. One study took a proactive approach at the beginning of the project to reduce the power imbalances by creating neutral spaces in which all participants views were considered equally [57]. Exemplar studies in this paper have shown that shared decision making with young people is beneficial to building their skillset, agency and confidence, particularly important for young people as they transition towards adulthood.
The review also identified deliberative priority setting methods that may not work so well for all young people. For example, digital means of engagement may not work as well for young people in low resource settings and in the global south where access to internet connections and reliable digital technology is limited. It is also clear that it should not be assumed that this excludes all forms of digital communications; use of platforms such as WhatsApp has been shown to work surprisingly well as part of interventions to improve adolescent health in South Africa [77]. Digital communications may, however, need to be adapted if they are to be inclusive of young people with sensory needs such as speech and sight challenges. Specific work needs to be carried out with these young people to develop deliberative priority setting processes that work for them. Other issues were identified in using deliberative processes with young people. Short timeframes for involvement, for example, carrying-out a Delphi survey over two 30-minute periods [62] and a single 50-minute appointment [60], gave less opportunity for young people to build relationships with peers and adults and less chance to build their decision-making capabilities. Although this particular instance reflected the constraints of the research scope, funding and capacity, it does suggest that reaching a successful conclusion of these processes for young people takes time.

Strengths and weaknesses
A strength of this scoping review is that it was able to identify diverse deliberative techniques, and was able to give more breadth of the available literature and depth in terms of the amount of information, compared to a systematic review [37]. Our initial search in 2019 found only 13 studies up until 2019, yet when we updated the search in 2021, we found 17 more studies between 2019 and 2021. This suggests that there has been an increase in the use of priority setting with young people within this time. The update of the review is a strength to this paper. Two reviewers simultaneously screened the papers however, only one researcher screened 100% of the papers. Another five researchers divided up the task and screened 10%. A limitation of this study is that it was difficult to identify one method as being the most effective in increasing engagement with young people in priority setting. Instead, different features of the techniques were considered successful (see recommendations in Table 3 below). Abelson et al's approach to evaluating deliberative priority setting was important to structure the narrative synthesis to identify the key features in the papers [40]. Abelson's evaluation criteria were limited however, in how far they are able to specify the extent to which criteria have been met.

Implications
The WHO-UNICEF-Lancet Commission calls for young people to be involved in creating policy that concerns them and their health [3,4]. Efforts to involve young people in policy and decision-making and in research are currently hampered by a lack of awareness of methods for engaging them effectively [78]. This review suggests that genuinely deliberative methods involving dialogue and mutual respect between young people, parents and professionals which go further than consultation not only achieve consensus on priorities for action but are also the most satisfying and beneficial for participants. It is widely held that involving young people in healthcare and health policy-making will also produce services with which they want to engage. Findings from this review may also be useful to policy makers who seek ways to collaborate with a diverse group of young people in producing health policy in a way that reduces power imbalances. Deliberative priority setting processes are also thought to increase health equity and literacy young people the opportunity to build their skills, knowledge, understanding and gain confidence in their ability to control over their own lives [79]. The WHO report on engagement and participation for health equity acknowledges that involvement of those with the least heard voices including young people, can lead to more equitable public health policies [79]. Deliberative priority setting processes may not directly tackle economic inequalities and social determinants of the health of young people but they do involve in activities that improve access to and experience of services. A by-product of deliberative processes seems to be that young people may develop more meaningful relationships with parents, carers and peers, argued by the Association of Young People's Health to improve both their physical and mental health [12]. There is, in addition, growing evidence that meaningful participation of young people in decision-making promotes social cohesion, creates more equal communities and helps adolescents make better informed and more empowered transitions to adulthood [7]. Its notable that none of the studies covered by this review addressed the cost-effectiveness of these deliberative priority setting with young people. Information on cost-effectiveness would assist policy makers in deciding whether or not to adopt these types of approaches with young people. From this review, we have 10 recommendations (Table 3).

Conclusion
This review does not provide definitive answers to questions about the most effective way of engaging young people in deliberative priority setting. A range of features was identified, however, which appeared to be associated with high participant satisfaction, achieving genuine consensus and were felt to generate outcomes which genuinely reflected participants' priorities. The WHO, UNICEF and other global organisations wishing to engage young people in setting priorities for healthcare and health policy might benefit from designing their interactions with young people around these key features of deliberative priority setting processes.