Adapting public policy theory for public health research: A framework to understand the development of national policies on global health

National policies on global health appear as one way that actors from health, development and foreign affairs sectors in a country coordinate state action on global health. Next to a burgeoning literature in which international relations and global governance theories are employed to understand global health policy and global health diplomacy at the international level, little is known about policy processes for global health at the national scale. We propose a framework of the policy process to understand how such policies are developed, and we identify challenges for public health researchers integrating conceptual tools from political science. We developed the framework using a two-step process: 1) reviewing literature to establish criteria for selecting a theoretical framework fit for this purpose, and 2) adapting Real-Dato's synthesis framework to integrate a cognitive approach to public policy within a constructivist perspective. Our framework identifies multiple contexts as part of the policy process, focuses on situations where actors work together to make national policy on global health, considers these interactive situations as spaces for observing external influences on policy change and proposes policy design as the output of the process. We suggest that this framework makes three contributions to the conceptualisation of national policy on global health as a research object. First, it emphasizes collective action over decisions of individual policy actors. Second, it conceptualises the policy process as organised interactive spaces for collaboration rather than as stages of a policy cycle. Third, national decision-making spaces are opportunities for transferring ideas and knowledge from different sectors and settings, and represent opportunities to identify international influences on a country's global health policy. We discuss two sets of challenges for public health researchers using interdisciplinary approaches in policy research.