A guide in defining outcome-impact case reports (OICRs). An evidence-based report detailing any outcome or impact that has resulted from the work of one or more CGIAR centres. The purpose of an OICR is to document and evidence one or more outcomes/impacts of CGIAR research. This is useful for regular reporting, for building and maintaining an archive of CGIAR successes, outcome leads, i.e. observed changes with high potential to further mature over the next three to five years with some more investment, and also for helping to select cases for further study.