3. ROP in practice

With these foundations in place, the economic evaluation of prevention initiatives can be carried out at three main levels. Firstly, a "macro" level, that of national or international prevention policies. The approaches are statistical and complex, both in terms of time and impact. Then there are two "micro" levels: company prevention programs and elementary actions. Programs are a grouping, not always clearly identifiable, of elementary actions, with a coherent purpose.