This article describes the development and use of a rapid evaluation approach to meet program accountability and learning requirements in a research for development program operating in five developing countries. The method identifies clusters of outcomes, both expected and unexpected, happening within areas of change. In a workshop, change agents describe the causal connections within outcome clusters to identify outcome trajectories for subsequent verification. Comparing verified outcome trajectories with existing program theory allows program staff to question underlying causal premises and adapt accordingly. The method can be used for one-off evaluations that seek to understand whether, how, and why program interventions are working. Repeated cycles of outcome evidencing can build a case for program contribution over time that can be evaluated as part of any future impact assessment of the program or parts of it.