Contribution analysis is a structured approach to theory-based impact evaluation originally developed in Canada in the context of Results-Based Management (RBM) although there have been few examples of contribution analysis in practice since Mayne’s original paper (2001). We argue that contribution analysis adds value to other theory-based evaluation approaches by providing a more structured and rigorous approach to participatory evaluation planning, data analysis and reporting. It can be applied in the context of participatory strategic planning and performance monitoring as well as impact evaluation. Examples are drawn from Scotland and Canada in the performance context of RBM in Canada and Outcomes-Based Accountability (OBA) in Scotland. The authors argue that, as a participatory process, contribution analysis strengthens both conceptual and practical understanding of planning/managing for outcomes and implementation and change theories, thus helping to build collaborative capacity within and across partner organizations. For public managers, the contribution analysis process has a strong appeal and practical value when faced with the task of demonstrating the contribution of single organizations to addressing complex social issues while working in partnership with other public agencies facing multiple accountabilities.