The organisation needs to show accountability to the general public, funders, donors and other stakeholder groups. Development agencies are increasingly legitimising their activities towards their partner organisations and beneficiaries as well (downward accountability).
The organisation wants to demonstrate what changes its outputs have brought about for the target group and what contribution it has made to solving a problem. It wants to find out whether it was correct to implement the project and whether the activity should be continued. The organisation can gain additional legitimacy for its action with the findings from its impact assessment.
Things are studied wide-angle, i.e. on the entire results chain rather than its individual components. It is crucial for the evaluation that the methodology is rigorous, the design good and the processing carried out correctly. The evaluation must be perceived as credible, technically competent and independent.
The demands on the impact assessment can be satisfied better if it is carried out by independent experts rather than by directly involved individuals.