We experimented with the Train-of-Trainer (cascade) approach in different countries, usually in disadvantaged areas and through community-based organizations. This was a different challenge in enhancing capacity for all shelters (around 70 at the time) for unaccompanied refugee children across Greece, which were provided by approximately 20 NGOs.
The key innovation was that trainers intercepted their own training by upskilling their staff group every two months. It was the breadth of the reach that mattered: we reached cooks, domestics, drivers and administrators; the core but often neglected group of caregivers; and the more anticipated social workers, educationalists and psychologists. Crucially, training was joint (interprofessional) and contextualized.
A description of the process and what various stakeholders made of it:
https://doi.org/10.1177/13591045241242324
panosvostanis 