After having described the intervention logic, the assumptions are developed. Assumptions answer the question: "Which external factors, that are not under the direct control of the project management, could significantly affect the realisation of the intervention?"

1. Identify in the objective tree those objectives that are not included in the intervention logic (first column), but that are important for the realisation of the stated objectives in the intervention logic.

2. Identify other external factors, not included in the objective tree, but important for the success of the intervention through institutional analysis tools like the Environmental scan and the Coverage matrix.

3. Assess all external factors upon their importance and chance to be realised, using the algorithm depicted below.

Algorithm to assess external factors

4. Place these objectives as external factors at the appropriate level (project purpose, results, activities).