Abstract Background Certain populations are consistently under-represented in randomised controlled trials (RCTs), including people from minority ethnic backgrounds and those experiencing socioeconomic disadvantage, language barriers, or marginalisation within health systems. This under-representation contributes to widening health inequities. While UK guidance such as the National Institute for Health and Care Research INCLUDE resources supports more inclusive research, practical methodologies for embedding equity in trial design remain limited. This paper draws on two linked public involvement projects: Talking Trials (2021–2023), working with ethnically diverse urban communities in Cardiff, and Let’s Talk Research (2025), working with residents in a socioeconomically disadvantaged rural Welsh community. Methods Both projects used participatory methods including arts-based activities, deliberative dialogue, and co-production. Talking Trials incorporated thematic analysis of workshop reflections; both projects generated learning through reflective discussions with community partners. Results Community-based public contributors identified features that made research feel relevant and equitable: trusted relationships, time for dialogue, and support to understand complex concepts. Creative and dialogue-based approaches made research concepts accessible, reduced power imbalances, and supported contributors to move from unfamiliarity to active involvement. Sustained structures, such as advisory groups and community connectors, were important for maintaining trust and enabling continued engagement. Context strongly shaped involvement, with different forms of disadvantage requiring different types of support. Conclusions Community-engaged, arts-based, and context-sensitive methods can meaningfully enhance equity in trial design. Embedding involvement early, investing in trusted partnerships, and sustaining long-term structures support more relevant, acceptable, and inclusive trials. These findings offer practical methodologies for trial teams seeking to embed equity from the outset.

Background: Underserved groups remain under-represented in randomised controlled trials, contributing to widening health inequities. While UK wide guidance such as the National Institute for Health and Care Research INCLUDE resources supports more inclusive research, practical methodologies for embedding equity in trial design remain limited. This methodological paper draws on two linked public involvement projects; Talking Trials (2021–2023), working with ethnically diverse urban communities in Cardiff, and Let’s Talk Research (2025), working with residents in a socioeconomically disadvantaged rural Welsh community, to explore approaches for supporting equitable early-stage trial design. Methods: Both projects used participatory methods including arts-based activities, deliberative dialogue, and co-production. Talking Trials incorporated thematic analysis of workshop reflections; both projects generated learning through ongoing reflective discussions with community partners. Activities were undertaken as public involvement, with ethical approval obtained for the 2023 phase of Talking Trials. Results: Across settings, contributors identified features that made research feel relevant and equitable: trusted relationships, time for dialogue, and support to understand complex concepts. Creative and dialogue-based approaches made research concepts accessible, reduced power imbalances, and supported contributors to move from unfamiliarity to active involvement. Sustained structures, such as advisory groups and community connectors, were important for maintaining trust and enabling continued engagement. Context strongly shaped involvement, with different forms of disadvantage (migration, language, socioeconomic status) requiring different types of support. Conclusions: Community-engaged, arts-based, and context-sensitive methods can meaningfully enhance equity in trial design. Embedding involvement early, investing in trusted partnerships, and sustaining long-term structures support more relevant, acceptable, and inclusive trials. These findings offer practical, transferable methodologies for trial teams seeking to embed equity from the outset.

Many well-designed parenting interventions have demonstrated effectiveness in improving outcomes for parents and children. During the COVID pandemic, many group-based parenting interventions were rapidly transferred to remote delivery using online videoconferencing platforms. However, the evidence on the effectiveness of remotely delivered group-based parenting programmes, compared to face-to-face programmes, remains inconclusive. This trial aimed to assess the feasibility of delivering the Group Triple P intervention to parents/caregivers of young children to inform a potential, definitive trial of the effectiveness and cost-effectiveness of Group Triple P delivered remotely compared to face-to-face delivery. This study was a feasibility non-randomised trial, with embedded process evaluation. Parents/caregivers of a child (up to 12 years old) were recruited by Local Authority or independent provider research sites and self-selected remote or face-to-face delivery of the Group Triple P intervention. Data were collected at baseline and 16 weeks follow-up. The following feasibility outcomes were assessed: site recruitment, participant recruitment rates and retention at the 16-week follow-up, intervention adherence, fidelity and reach, feasibility of trial processes and outcome measures (including resource use, cost and health-related quality of life) and Local Authority and independent service provider willingness to participate in a definitive trial. All sites utilised a multi-point participant recruitment strategy, relying on existing pathways to identify families. Only two sites reached participant recruitment targets. Participants’ self-selected remote delivery (23 participants) or face-to-face delivery (19 participants) and baseline demographics, except for education level, were balanced across arms. A 66.7

Introduction Parkinson’s disease (PD) is the second most common neurodegenerative disorder, its principal symptom being deterioration of motor function. Current treatment options are limited to symptom management but there is evidence that physical activity can provide motor benefits. More recently there is evidence to suggest that rhythmic auditory stimulation may improve gait and balance in PD. Sparky Samba is a community initiative in South Wales, UK, founded by a person living with PD. Sessions incorporate the following samba rhythms from a trained facilitator and are held weekly in a community setting.Methods The Sparky Samba trial is a multi-site, non-blinded, randomised controlled feasibility trial of Sparky Samba compared with activity as usual. A total of 60 people with PD will be randomised 1:1 to take part in a local Sparky Samba group for 12 weeks or continue their normal activities for the same length of time. The primary outcome is feasibility defined by recruitment, retention, data completeness and intervention adherence. Secondary outcomes relating to motor function, cognition, well-being and self-efficacy will also be assessed at baseline and at 12 weeks. Additionally, we will conduct a process evaluation to understand contextual mechanisms surrounding Sparky Samba. This will be achieved through qualitative interviews and structured participant questionnaires following individual trial completion and through structured questionnaires with intervention delivery staff, supplemented with qualitative interviews.Analysis Feasibility outcomes will be assessed according to pre-defined criteria. For secondary outcomes, means and standard deviations (or medians and IQRs) will be calculated by arm, alongside 95% CIs for change from baseline to 12-week follow-up. Qualitative data will be subject to thematic analysis using NVivo software.Ethics and dissemination This study received a favourable ethical opinion from the North of Scotland Research Ethics Committee in April 2025 (REC reference 25/NS/0037). Study results will be disseminated through the peer-review literature, the ISRCTN registry and directly to participants, which will be facilitated by the study’s public and patient involvement steering group.Trial registration number ISRCTN11861663

TRAK MSK is a co-designed digital physiotherapy supported self-management programme. It enables people to develop the knowledge, confidence and skills to self-manage their condition and pain, to improve everyday function and physical activity levels. We explored the feasibility of conducting a definitive trial of the TRAK MSK intervention. We conducted a two-arm multi-site randomised external feasibility trial with an embedded process evaluation. We recruited adults aged 18 and over with self-reported activity related joint pain for at least 3 months, attending physiotherapy clinics. Participants were randomised to either the TRAK MSK intervention or usual NHS physiotherapy care. The TRAK MSK intervention was delivered over 16 weeks and included up to five online coaching consultations with a physiotherapist trained in self-management support, and access to a website designed to support these consultations. Primary feasibility outcomes were recruitment, randomisation and retention at 16 weeks post-randomisation, all of which were pre-defined. Secondary outcomes were feasibility of collecting health services resource use and intervention costs and reported variability of participant rated questionnaires at baseline and follow up. We evaluated acceptability of intervention receipt and trial processes and intervention fidelity with an embedded process evaluation. We consented 87 (59

Background:People leaving prison face significant barriers to reintegration, often resulting in homelessness, which exacerbates health issues and increases recidivism. Critical time interventions aim to support vulnerable individuals during significant life transitions by providing time-limited, emotional and practical support. While effective in other contexts, the impact of housing-led critical time interventions for people leaving prison in the United Kingdom remains unclear. The PHaCT study was a pilot randomised controlled trial of a housing-led critical time intervention for people leaving prison at risk of homelessness. This study aimed to determine whether a full-scale randomised controlled trial of the critical time intervention model in prison leavers at risk of homelessness was feasible. Methods:The pilot was a parallel two-arm, individual-level randomised controlled trial of a pre-existing critical time intervention intervention with an integrated process evaluation and embedded exploratory health economic evaluation. Recruitment occurred in fours male prisons across England and Wales with participants followed up in the communities. Prisons were randomised by site to either receive the critical time intervention or receive usual support, and participants were recruited within 12 weeks of their release. The locations were predetermined by where the intervention was already being delivered by the intervention provider (critical time intervention teams). Critical time intervention included pre-engagement, transition to community, try-out and transfer of care phases, each lasting 3 months. Data collection methods included baseline surveys, follow-up assessments at 3, 6 and 9 months, qualitative interviews, and session observations. Routine data linkage was explored separately to assess feasibility. Progression criteria included recruitment, retention, process evaluation and fidelity. Results:Thirty-four male participants (mean age 38 years) were recruited, with 19 assigned to the intervention and 15 to control. The study achieved a high recruitment rate of 92%, but retention was a significant challenge, with only 18% of participants retained at 9 months follow-up. The process evaluation found critical time intervention was acceptable to staff and participants, but ethical concerns around randomisation and informed consent were raised. Fidelity to the critical time intervention model was generally high, though contextual instability in housing and criminal justice systems posed challenges. Data collection methods for health economics and data linkage were feasible and acceptable. Limitations:The approval to access prisons was lengthy and support provided by Clinical Research Networks was delayed. Contextual instability within the housing and criminal justice systems, including a lack of social housing, high recall rates, the removal of the requirement to have a probation officer and the emergency early release of people in prison, further complicated the trial. Ethical concerns around randomisation and informed consent affected trial acceptability. Conclusions:The trial methodology faced significant challenges. Low retention rates, ethical concerns by intervention delivery staff around randomisation and contextual instability suggest that a full-scale randomised controlled trial is not feasible. Implications/future work:The findings highlight the need for systemic changes within the research support provided to prison-based studies, housing and criminal justice systems to support research in prisons and interventions for people leaving prison. Decision-makers should prioritise policies that increase the availability of affordable housing and provide post-release support. Future research should explore alternative study designs and more intensive recruitment and retention strategies. Funding:This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme as award number NIHR134281.

To provide high-quality care to people living in care homes, it is crucial that care home staff possess the knowledge and skills necessary to apply the principles of mental capacity legislation. In order to achieve this, training must be delivered and implemented. This review aimed to identify what is known about the design, delivery and implementation of mental capacity-related education and training in care homes. A scoping review was conducted in line with Joanna Briggs Institute guidance, and reported in accordance with PRISMA-ScR. A total of 3055 records were retrieved by the search and independently screened by two reviewers. A total of 14 papers met the inclusion criteria and were included in the review. Results were synthesised and mapped to the TIDieR checklist. The results highlighted two key factors. Firstly, a standardised one-size-fits-all approach to mental capacity legislation training fails to take account of the diverse needs of both care home residents and staff. Secondly, understanding the relationships between these domains can help overcome barriers and enhance facilitators, leading to more effective training outcomes. The review highlights a knowledge gap, with limited research considering the design and delivery of mental capacity related training. This limits the development of consistent and effective training across the sector. Future research should consider issues of diversity among care home staff or residents, to ensure the appropriateness and applicability of training for all those who receive it.

Background We conducted a pilot randomised controlled trial (the PHaCT study), including a process evaluation to assess the acceptability of a housing-led Critical Time Intervention (CTI) for prison leavers and the use of a trial design. This paper presents the process evaluation findings.Objective To explore the acceptability of both the intervention and the trial design to participants and those delivering the intervention, and to assess whether the intervention was delivered with fidelity.Design A process evaluation following Medical Research Council guidelines. Data collection included semi-structured interviews with participants and CTI caseworkers and observations of intervention delivery. A thematic analysis of interviews and observations was conducted to understand the intervention’s implementation and contextual factors as well as the trial process acceptability.Setting Participants for the pilot trial were recruited from three prisons in England and Wales where the intervention was being delivered.Participants While 28 out of 34 trial participants consented to interviews, only one was completed. Seven caseworkers were interviewed.Intervention A housing-led CTI to support people leaving prison at risk of homelessness, involving phased, time-limited support from caseworkers, starting prerelease and continuing postrelease, to help secure stable housing and build independence, without directly providing housing.Results The intervention’s acceptability was primarily reflected through the positive feedback and success stories shared by CTI caseworkers, as well as observational data indicating high acceptance among service users. The trial design’s acceptability was challenged by concerns about randomisation and equipoise, with staff viewing randomisation as unethical due to limited support for vulnerable populations. The fidelity to the CTI intervention housing-led approach was adhered to as best as possible; stable housing was prioritised for service users before addressing other needs. Despite these efforts, both sites encountered significant challenges due to limited housing availability and complex systems for securing social housing, particularly for single men leaving prison.Conclusions This wider study faced significant challenges which impacted the process evaluation. Despite these issues, the evaluation provides important insights into the challenges of conducting trials on interventions for people leaving prison. The challenges experienced should inform future study designs with similar populations and in similar settings.Trial registration number ISRCTN46969988.

Background:Variation in the way information about potential trial intervention benefits and harms is conveyed within patient information leaflets can cause avoidable information-induced ('nocebo') harm, research waste, and may be unethical. Objectives:1. To develop stakeholder-informed principles to guide how to describe information about potential trial intervention benefits and harms within patient information leaflets. 2. To test whether using these principles are feasible for testing in trials that measure whether they improve recruitment and adverse event rates. 3. To develop and disseminate guidance on how to implement the principles. Methods:We used a mixed methodology consisting of three work packages. Work package 1 involved a modified Delphi survey and consensus meeting to develop the principles for harmonising the way information regarding potential benefits and harms are shared. Work package 2 involved testing whether the principles could be used to transform existing patient information leaflets by recruiting host trials to compare standard patient information leaflets with patient information leaflets developed using the principles 'principled patient information leaflets'. We also set up an infrastructure to test whether they could reduce variation, impact trial recruitment and reduce reported adverse events. Work package 3 involved developing and disseminating guidance for using the principles. Results:For work package 1, 250 participants completed the Delphi survey and 7 principles were agreed upon: (1) all potential intervention harms should be listed, (2) potential harms should be separated into 'serious' and 'less serious', (3) if not all potential harms are known, this needs to be explicitly stated, (4) all potential benefits should be listed, (5) potential benefits and harms associated with trial participation need to be compared with those associated with non-participation, (6) suitable visual representations should be added where appropriate, and (7) information about potential benefits and harms should not be separated by more than one page. For work package 2, we developed principled patient information leaflets for five host trials and interviewed two members of each host trial team. Two host trials agreed to compare the patient information leaflets with principled patient information leaflets using Studies Within a Trial, and we published a protocol for a meta-analysis that will synthesise the results. For work package 3, 25 participants attended a hybrid workshop and recommended that researchers and Research Ethics Committee members should use the principles to design and evaluate patient information leaflets. We produced a guidance booklet and website, which are currently being used by some Health Research Authority Research Ethics Committees. Conclusions:A strong consensus was reached regarding seven principles that can harmonise the way information about the potential benefits and harms of trial interventions is shared. The principles are likely to reduce research waste and avoidable information-induced harm, and may enhance clinical trial ethics. Limitations:Due to COVID-19, the National Institute for Health and Care Research review of ongoing trials that resulted in funding termination for several trials, and highly pressured trial staff with limited capacity to add Studies Within a Trial to their trials, we had to modify our second objective. Whereas we initially intended to actually conduct the Studies Within a Trial, we replaced this with: a protocol for a meta-analysis of Studies Within a Trial, additional research on the need to reduce variation, additional dissemination work, and a paper on the ethical requirement to mention potential benefits and harms of trial interventions in patient information leaflets. Future work:Future work could apply these results to explore how to harmonise the way potential benefits and harms are shared during verbal conversations between researchers and patients during the informed consent process. Funding:This award was funded by the Medical Research Council and the National Institute for Health and Care Research (NIHR) Better Methods, Better Research programme (MRC Award Reference: MR/V020706/1) and is published in full in Health Technology Assessment; Vol. 29, No. 43.

Objective To determine whether a full-scale randomised control trial (RCT) assessing the efficacy and cost-effectiveness of a housing led Critical Time Intervention (CTI) is feasible and acceptable.Design Pilot parallel two-arm individual level RCT, including process evaluation and embedded exploratory health economic evaluation.Setting Four prisons for men across England and Wales, UK.Participants Men leaving prison at risk of homelessness and intervention delivery staff.Intervention CTI has four components: (1) pre-engagement phase: assessing the needs of the client and implementing a plan pre-discharge; (2) transition to community: forming relationships and goal setting; (3) try out: encouraging problem-solving and managing practical issues and (4) transfer of care: developing long-term goals and transferring responsibilities to community providers.Outcome measures Progression criteria: recruitment, retention, acceptability of the processes (CTI and trial method) and fidelity of intervention delivery. We also assessed the completeness of primary, secondary and exploratory outcome measures and estimated intervention costs.Results The recruitment progression criterion was met, with 92% (34/37) of approached individuals consenting to participate (target: 50%). However, the overall recruitment target of 80 was not achieved, and retention was low, only 18% (6/34) provided follow-up data, well below the 60% threshold. Retention was hindered by systemic challenges, including changes to prison release policies and reduced probation support. While the CTI model was acceptable to staff and service users, the trial design, particularly randomisation, was not. Intervention fidelity met the progression criteria. Baseline data collection for health economics and resource use was feasible, and intervention costs were estimated.Conclusion This pilot trial identified significant challenges to conducting a full-scale RCT of CTI in this context, particularly around retention, trial acceptability and systemic instability. While CTI remains a promising model, a traditional RCT design may not be viable in this setting without substantial structural and ethical adaptations.Trial registration number ISRCTN46969988.

OBJECTIVE:Mental Capacity legislation defines when a person lacks capacity and subsequently supports individuals to make as many decisions as possible for themselves. Whilst frameworks exist, care home staff often feel unsupported with insufficient knowledge and training. This review aimed to understand barriers and facilitators of implementing mental capacity legislation in care homes for older adults in the United Kingdom. METHODS:A systematic review was conducted and 3041 potentially relevant studies identified, with 13 studies eligible for inclusion. 11 focused on the Mental Capacity Act (2005) and two on the Adults with Incapacity (Scotland) Act 2000. Barriers and/or facilitators were extracted and subsequently mapped to the Capability, Opportunity and Motivation model and Theoretical Domains Framework. RESULTS:Barriers included poor access to training, low staff confidence and a lack of understanding about using legislation in context. Conversely, staff reported in-person training using real-life examples, robust organisational policies and processes and respecting person-centred care were key facilitators. Sense-checking conversations were conducted with care home staff (n = 18) to interpret findings in the context of current practice. CONCLUSIONS:This review presents complex and multi-faceted barriers preventing the implementation of mental capacity legislation in care homes for older adults. Whilst care home staff have now started to appreciate the importance of such legislation, insufficient time, resources and an inability to track staff knowledge prevents effective implementation of the law. Future research should explore how staff are trained about legislation and identify best practices.

Amidst a global nursing shortage, ensuring sufficient nurses are available to care for patients is an international policy priority. High-income countries have developed and implemented numerous models to ensure safe nurse staffing, yet evidence to recommend any single methodology remains limited. Existing research primarily evaluates nurse staffing systems by inputs and outcomes, neglecting their internal dynamics. Using qualitative case study data from England and Wales and drawing on practice perspectives and Actor Network Theory, this paper examines these socio-material relations. Healthcare systems are complex, diverse and constantly evolving. Whilst identifying a single 'best' model may prove both impractical and elusive, this paper demonstrates the value of this theoretical approach for understanding the interplay of system components and the mediating effects of context. These insights can inform future research and help improve systems to meet the demands of late modernity.

Clinical trial participants must understand the possible risks and benefits of trial interventions before providing their informed consent to participate. The aim of this commentary is twofold: to summarize the discrepancies in the extent to which patient information leaflets (PILs) list potential benefits and harms of trial interventions; and to highlight subsequent ethical issues that may result from failure to disclose potential benefits or harms . A review of 247 patient information leaflets (PILs) found that the extent to which potential benefits and harms are described varies, with 28 (11

BACKGROUND:A diverse range of formal systems have been implemented in high income countries to ensure safe nurse staffing. Evidence reviews indicate that no one best model exists and recommends optimising existing systems. As a result of the Covid-19 pandemic and a global nursing workforce crisis, healthcare systems and the nursing profession face a challenging future. Nurse staffing systems must be fit for purpose. AIM:Identify, describe and compare the core components of nurse staffing systems, assess the conditioning effects of context on their mechanisms of action, and explore front-line implementation experiences to inform system optimisation. SAMPLE:Ten widely used nurse staffing systems deployed in high-income western healthcare systems. THEORY:Complex interventions thinking and Actor Network Theory. METHODS:Phase 1: Document analysis of formal published accounts of nurse staffing systems. Phase 2: Focused interpretative review of evidential fragments on implementation experiences and contextual influences from available evaluation studies. CONCLUSIONS:Systems varied in their complexity, core components, and organising logics. Nurses experience a range of implementation challenges, but workforce shortages and budgetary constraints were the principal contextual influences. Prospective strategies to optimise nurse staffing systems must be tailored to system and context but include strategies and tools to augment professional authority, more granular workload measurement, improved outcome measurements, strengthened digital infrastructures, enhanced governance arrangements and increased public accountability. Benchmarking approaches should be used with caution, given the normative impulse to depress staffing levels. In the context of a global workforce shortage, consideration should also be given to the impacts of nurse staffing models on the wider healthcare system. TWEETABLE ABSTRACT:How can we optimise safe nurse staffing systems? Insights from a document analysis and interpretative review informed by actor network theory.

Background: A diverse range of formal nurse staffing models have been implemented in high income countries to ensure safe nurse staffing. Evidence reviews indicate that no one best model exists. As a result of the Covid-19 pandemic and a global nursing workforce crisis, healthcare systems and the nursing profession face a challenging future. It is essential that extant systems are fit for purpose.Aim: Develop a comparative understanding of nurse staffing systems as complex interventions to inform system optimisation and future research.Sample: Ten widely used nurse staffing systems selected through a scoping review and international advisory group.Theory: Complex interventions thinking and Actor Network Theory.Methods: Phase 1: Systematic theoretically informed-documentary analysis of formal published guidance (policy, legislative, institutional), supplemented by additional material (grey literature, research papers) for clarificatory purposes. Phase 2: Focused interpretative review of available evaluation studies to understand implementation experiences and the conditioning effects of context.Conclusions: Included systems varied in their complexity, core components and organising logics, but all were conditioned by contextual constraints which impacted implementation. We build on the review to make recommendations for optimising existing systems in practice and strategies for future research.

Purpose (the aim of the study): TRAK-MSK is a co-produced theory-based digital physiotherapy self-management intervention. It is intended to help people with joint pain have the knowledge, confidence and skills to self-manage their condition so that they are more physically active and experience less pain. Our aim was to evaluate the feasibility and acceptability of conducting a multi-centre randomised controlled trial of TRAK MSK compared to usual care.

Background/aims The value of using qualitative methods within clinical trials is widely recognised. How qualitative research is integrated within trials units to achieve this is less clear. This paper describes the process through which qualitative research has been integrated within Cardiff University's Centre for Trials Research (CTR) in Wales, UK. We highlight facilitators of, and challenges to, integration.Methods We held group discussions on the work of the Qualitative Research Group (QRG) within CTR. The content of these discussions, materials for a presentation in CTR, and documents relating to the development of the QRG were interpreted at a workshop attended by group members. Normalisation Process Theory (NPT) was used to structure analysis. A writing group prepared a document for input from members of CTR, forming the basis of this paper.Results Actions to integrate qualitative research comprised: its inclusion in Centre strategies; formation of a QRG with dedicated funding/roles; embedding of qualitative research within operating systems; capacity building/training; monitoring opportunities to include qualitative methods in studies; maximising the quality of qualitative research and developing methodological innovation. Facilitators of these actions included: the influence of the broader methodological landscape within trial/study design and its promotion of the value of qualitative research; and close physical proximity of CTR qualitative staff/students allowing sharing of methodological approaches. Introduction of innovative qualitative methods generated interest among other staff groups. Challenges included: pressure to under-resource qualitative components of research, preference for a statistical stance historically in some research areas and funding structures, and difficulties faced by qualitative researchers carving out individual academic profiles when working across trials/studies.Conclusions Given that CTUs are pivotal to the design and conduct of RCTs and related study types across multiple disciplines, integrating qualitative research into trials units is crucial if its contribution is to be fully realised. We have made explicit one trials unit's experience of embedding qualitative research and present this to open dialogue on ways to operationalise and optimise qualitative research in trials. NPT provides a valuable framework with which to theorise these processes, including the importance of sense-making and legitimisation when introducing new practices within organisations.

Background The way potential benefits and harms of trial interventions are shared within patient information leaflets (PILs) varies widely and may cause unnecessary harms (“nocebo effects”). The aim of this meta-analysis will be to evaluate the influence on recruitment rates and early effects on patient reported adverse events of principled patient information leaflets (PrinciPILs) compared with standard PILs. Methods Eligible studies will include those that report the effects on recruitment and patient reported adverse events of PrinciPILs compared to standard PILs. We will include in this meta-analysis all the standard PILs in studies within trials (SWATs) of PrinciPILs that were developed as part of the Medical Research Council (MRC) funded PrinciPIL project. By publishing this as a living meta-analysis, we will allow the meta-analysis to be updated with future SWATs of PrinciPILs. We will use the Cochrane Risk of Bias tool to evaluate the risk of bias for each outcome. We will report the total number of studies and participants analysed and the characteristics of included studies (including details of intervention, comparators, outcomes). For dichotomous data, we will calculate the risk difference and the risk ratio (RR) and 95% confidence intervals (CIs). For continuous outcomes we will use weighted mean differences with 95% CIs or standardized mean differences with 95% CIs. We will investigate heterogeneity by visually inspecting the forest plot and by considering the I2 test result. We will assess the certainty warranted for each outcome using the Grading of Recommendations Assessment Development and Evaluation (GRADE). Ethics approval is not applicable since no original data will be collected. The results will be disseminated through peer-reviewed publication and conference presentations. Discussion We will discuss the limitations of the meta-analysis including study risk of bias, inconsistency, heterogeneity, and imprecision. A general interpretation of the results and important implications will be provided.

Background: The way information about potential benefits and harms of trial is presented within participant information leaflets (PILs) varies widely and may cause unnecessary ‘nocebo’ effects. The Medical Research Council (MRC) funded a project that developed seven principles to reduce this variation. However, guidance has not been produced to facilitate the implementation of the principles. Stakeholder involvement is recommended to optimise the way these principles are disseminated and explained. To co-produce recommendations for developing: (1) user-friendly guidance for users of the principles; and (2) resources that support the implementation of the principles. Methods: We held a co-production workshop with representation from the following professional groups: the Health Research Authority (HRA), research ethics committee members, and trial managers. Two rounds of discussions focused on generating recommendations for guidance and resources that support the implementation of the seven principles. Extensive low inference style ethnographic notes were taken, and the data were analysed thematically using deductive codes. The data was collected on October 14, 2022. Results: 25 participants attended a hybrid workshop. Participants recommended that both researchers designing PILs and research ethics committee members should use the principles, and that that they should be simple, mention both benefits and harms explicitly, include examples of visual representations, and provide the evidence base for the principles. Conclusions: We were able to co-produce recommendations for developing and implementing the seven principles within PILs. These recommendations can now be implemented to reduce unexplained variation in the way potential benefits and harms are shared within PILs.