{
  "abstract": "Introduction Health inequalities remain resistant to interventions that primarily target individual behaviour. Although systems approaches are increasingly promoted, their application in practice is often not well grounded in real-world settings. In this protocol paper, we present the approach we will take in an overarching project that synthesises the combined insights of four ongoing systems-based research projects on system-based approaches for reducing health inequalities in the Netherlands. By bringing together and comparing findings across diverse contexts, populations and interventions, we aim to generate an empirically grounded understanding of what works, for whom, in what contexts and why, and to derive actionable strategies for systemic change to reduce health inequalities.Methods and analysis We use a realist approach to synthesise insights from the four ongoing projects. The design involves four iterative steps: (1) Identifying cross-cutting themes from project proposals and literature, (2) Developing and refining context–mechanism–outcome (CMO) configurations through literature review and Slow Science meetings, (3) Engaging Critical Friends to co-develop actionable strategies and (4) Assessing and validating these strategies across diverse contexts. Iterative feedback loops ensure continuous refinement, integration of stakeholder perspectives and exploration of emergent challenges. This design enables theory-informed, practice-based strategies to support sustainable system change in reducing health inequalities.Ethics and dissemination Ethical approval for the four underlying projects has been obtained from the relevant institutional review boards, and the way their data is used for this overarching project falls within their approved scope. Dissemination will be ongoing and co-created with stakeholders, including policy briefs, factsheets, educational tools and academic publications, to support uptake of strategies for systems change.",
  "authors": [
    {
      "affiliations": [
        "Department of Health Promotion, Maastricht University, Maastricht, the Netherlands"
      ],
      "name": "Stijn S Horck"
    },
    {
      "affiliations": [
        "Department of Health Promotion, Maastricht University, Maastricht, the Netherlands",
        "Department of Public Health and Primary Care/Health Campus The Hague, Leiden University Medical Centre, Leiden, the Netherlands"
      ],
      "name": "Matty Crone"
    },
    {
      "affiliations": [
        "Department of Interdisciplinary Social Science: Public Health, Utrecht University, Utrecht, the Netherlands"
      ],
      "name": "Carlijn B M Kamphuis"
    },
    {
      "affiliations": [
        "Department of Interdisciplinary Social Science: Public Health, Utrecht University, Utrecht, the Netherlands"
      ],
      "name": "Gonneke W J M Stevens"
    },
    {
      "affiliations": [
        "Department of Ethics, Law and Humanities, Amsterdam UMC, Amsterdam, the Netherlands"
      ],
      "name": "Christine Dedding"
    },
    {
      "affiliations": [
        "Department of Public Health and Primary Care/Health Campus The Hague, Leiden University Medical Centre, Leiden, the Netherlands",
        "The Institute of Public Administration, Leiden University, Leiden, the Netherlands"
      ],
      "name": "Jet Bussemaker"
    },
    {
      "affiliations": [
        "Department of Public Health and Primary Care/Health Campus The Hague, Leiden University Medical Centre, Leiden, the Netherlands",
        "Faculty of Social Work and Applied Psychology, Leiden University of Applied Sciences, Leiden, the Netherlands"
      ],
      "name": "Suzan van der Pas"
    },
    {
      "affiliations": [
        "Department of Interdisciplinary Social Science: Public Health, Utrecht University, Utrecht, the Netherlands",
        "Chair Group Consumption and Healthy Lifestyles, Wageningen Universiteit and Research"
      ],
      "name": "Jantien van Berkel"
    }
  ],
  "title": "Exploring what works, for whom, under what circumstances to transform systems: realist synthesis protocol of four ongoing studies and literature addressing health inequalities",
  "uid": "5e709d11-5172-5b3d-8b3e-072652549439"
}