Developed by international experts, and supported and financed by development institutions, travelling models are exported to low-income countries on a massive scale as "ready-made" solutions. A travelling model, which is often the result of a foundational experience, is manufactured around a mechanism endowed with intrinsic efficiency and the necessary operational tools for its implementation. It is then disseminated in various contexts by networks of professionals and decision-makers. The confrontation with local contexts, that is to say the actors in the field, produces inevitable implementation gaps, many unforeseen effects, and results that can be disappointing or far removed from the initial objectives – as illustrated by the numerous case studies presented in this issue, based on original empirical data collected across the world.
