1) Evaluation and impact assessment approaches can be categorized based on their goals (formative, summative, developmental) and methods (qualitative, quantitative, mixed). 2) In organizations like the CGIAR, impact assessment was initially implemented to ensure accountability but now aims to facilitate organizational learning. 3) For impact assessment to influence organizational change in the CGIAR, it needs to help build consensus on needed reforms, develop new frameworks for analyzing social processes, and work with coalitions of supportive stakeholders.