Role of trust and trustworthiness in implementation science studies: a systematic review protocol.

INTRODUCTION: Implementation science seeks to promote the adoption and sustainment of evidence-based interventions across diverse settings. While technical and organisational determinants of implementation have been extensively studied, relational factors-particularly trust and trustworthiness-remain under-theorised despite being frequently invoked in implementation research. Trust is often embedded implicitly within broader constructs such as stakeholder engagement, partnership quality or acceptability, yet is rarely explicitly defined, systematically measured or positioned clearly within implementation frameworks. No systematic review has comprehensively synthesised how trust functions within implementation science studies.

METHODS AND ANALYSIS: This systematic review protocol follows Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 guidelines and is registered with PROSPERO. We will conduct a targeted search on Scopus for 14 journals that are recognised by experts as being the most relevant in publishing implementation science literature. Supplemented by hand searching through Global Implementation Research and Applications. Studies examining trust or trustworthiness as a variable (explicitly or implicitly through related constructs) in relation to implementation processes or outcomes will be included. Two reviewers will independently screen titles/abstracts and full texts using Rayyan. Data extraction will capture trust conceptualisation, measurement approaches, levels of operation, constituent perspectives and inferred relationships with implementation outcomes. Quality assessment will use design-appropriate tools (Critical Appraisal Skills Programme for qualitative studies, Mixed Methods Appraisal Tool for mixed-methods). Given anticipated heterogeneity, we will conduct narrative and thematic synthesis rather than meta-analysis, exploring patterns by study design, setting, theoretical underpinnings, implementation phase and trust level.

ETHICS AND DISSEMINATION: This systematic review of published literature does not require ethical approval. Findings will be disseminated through peer-reviewed publications, conference presentations at implementation science networks and non-technical summaries for community partners and policymakers.

PROSPERO REGISTRATION NUMBER: PROSPERO 2025 CRD420251270920.