How should policymakers, funders, and research teams mobilize to build the evidence base on universal early years services?

Health visiting in England is a universal service that aims to promote the healthy development of children aged under five years and safeguard their welfare. We consulted stakeholders about their priorities for research into health visiting and also used these consultations and a literature review to generate a logic model. Parents wanted research to explore how health visiting teams can provide a caring, responsive, accessible service (the mechanisms of change). Policymakers, commissioners, and clinical service leads wanted descriptions and evaluations of currently implemented and ‘gold standard’ health visiting. The challenges to evaluating health visiting (data quality, defining the intervention, measuring appropriate outcomes, and estimating causal effects) mean that quasi-experimental studies that rely on administrative data will likely underestimate impact or even fail to detect impact where it exists. Prospective and experimental studies are needed to understand how health visiting influences infant–parent attachments, breastfeeding, childhood accidents, family nutrition, school readiness, and mental health and well-being.