Abstract In this commentary, we draw on examples from the thematic issue ‘Longitudinal studies in ECEC—challenges of translating research results into policy actions’ to discuss how research from longitudinal studies in ECEC can potentially inform policy making. Thereby, we point out the challenges in the relationship between research and policy and suggest three key factors that can promote the impact of meaningful research in policy decisions. The first factor comprises aligning research questions with policy priorities as well as research and policy making processes. In an attempt to systematise existing forms of research and policy interaction, we present ideal–typical models of collaboration and relate them to studies in this thematic issue. Second, we argue that research used in policy decisions should rely on sound methodology, including state of the art techniques of sampling as well as reliable and valid measures. While acknowledging that various research designs are required to get a bigger picture of the complexity of ECEC, we call attention to the particular potential of longitudinal studies to inform policy making. Third, we stress the importance of disseminating research results to different stakeholders and outline challenges of translating research findings into policy decisions. Finally, in the outlook, we discuss how collaboration between ECEC research and policy making can be increased and which barriers need to be overcome.