Synthesis of conceptual, methodological and pedagogical works on scaling up complex public health interventions: a...

In public health, the scaling up of interventions can bring progress for the health of populations on the basis of promising experiments, by meeting major health, ethical and economic challenges. However, there is no systematic procedure, like those established for drug development, to guide development of a public health intervention with the aim of scaling it up, nor is there a benchmark approach to establish the validity of an intervention for scaling up. We performed a literature review to analyse the concept of scaling up in the public health field.

The materials included were published between 2000 and 2021 and present conceptual frameworks and models, guides and tools developed for scaling up public health interventions. Three main objects were analysed through these publications: the meanings of the concept of scaling up, success factors or barriers to scaling up, and the steps or phases of work in the scaling up process.

This research explored 24 bibliographical references: 16 scientific articles, 5 guides or tools, 2 public health science theses and 1 book chapter. Two main approaches were defined: scalability and scaling up. 29 success factors and 28 obstacles to scaling up were identified. Finally, 10 work phases in the scaling up of a public health intervention were described.

In order to embrace the different nuances highlighted in the existing literature, we propose a new definition of public health intervention scaling up. It concerns all levels from local to global. It is not a spontaneous process, but requires active dissemination of the intervention in space, in time and in real world conditions. Several avenues for future research are proposed. They concern the practices of the different stakeholders, specifics of the process according to the scale concerned, the arcana of the scaling up decision, and the connections between the concept of scaling up and other notions in the field.