Effect of strengths-based, tiered, accessible resources and supports (STARS) for Kids project, a codesigned hybrid service delivery framework to identify and support child development, parent mental health and psychosocial needs among parents and carers of children aged 6 months to 3 years: a randomised controlled trial protocol.

INTRODUCTION: Inequitable access to early developmental support persists across both universal and specialised services for priority populations. However, real-world evidence on the impact of implementing proportionate universalism framework (universal plus targeted supports commensurate with needs) within service systems is limited. To address this gap, we aim to implement and evaluate a codesigned model of care called the Strengths-based, Tiered, Accessible Resources and Supports for Kids (hereafter, STARS for Kids) model to improve early identification and delivery of appropriate support for child developmental vulnerabilities, parental mental health and family psychosocial needs across the first 2000 days of life, from pregnancy to the start of school.

METHODS AND ANALYSIS: This study will be conducted in three phases alongside the codesign phase that will be integrated across the life of the study. First, the impact evaluation phase will be conducted using a multisite, individually randomised controlled trial to evaluate the effectiveness of the STARS for Kids tiered care model (intervention group) against enhanced usual care (control group). Parents/carers of children aged 6 months to 3 years (140 per site) will be recruited using opportunistic contacts in three sites: (i) a multicultural site with a high immigrant population in South Western Sydney in New South Wales (NSW), Australia; (ii) a regional/rural site including an Aboriginal community on Biripi land in Taree in NSW; and (iii) a low socioeconomic site, the City of Wanneroo in Western Australia. Additionally, a nested trial will evaluate the My Toddler and Me Enhanced Video Programme intervention against enhanced usual care among children identified with emotional dysregulation. Second, the implementation evaluation phase will be conducted with consumers and service providers (approximately 15-20 per group and site). Underpinned by the consolidated framework for implementation research, it will evaluate the perceived feasibility, satisfaction, benefits, barriers and facilitators of the model. Third, the economic analysis and dynamic simulation modelling phase will ascertain the cost-benefits and model the impact of the STARS for Kids intervention across the life course for children and families. The primary outcome (parent or carer-reported completion of child developmental checks) and secondary outcomes (changes in child developmental vulnerabilities, parental mental health and family psychosocial needs between the intervention and control groups) will be compared by intention-to-treat analysis using generalised mixed models to account for group, time and interactions. Interview data from the implementation evaluation phase will be thematically analysed to identify, refine and integrate themes representing participant experiences.

ETHICS AND DISSEMINATION: The South Western Sydney Local Health District Human Research Ethics Committee approved this protocol for the South Western Sydney and Taree sites in NSW (2024/ETH01146) and Ramsay Ethics approved this protocol for the Wanneroo site in Western Australia (2025/ETH/0002). Site-specific research governance approvals were granted for all three sites. Given the substantial proportion of Aboriginal and/or Torres Strait Islander communities in Taree, an Aboriginal Health and Medical Research Council ethics application was approved for the Taree site (2478/25). Findings from this study will be published in reports and refereed journals and presented at appropriate conferences and community forums following consultations with the relevant steering committees and consumer groups.

TRIAL REGISTRATION NUMBER: ACTRN12624000806561.