Oxfam Great Britain has a global portfolio comprised of over 250 programmes and 1,200 associated projects that operate in 55 countries across diverse thematic aims. Despite the challenges posed by the scale, breadth, and complexity of this work, we are strongly committed to being accountable and getting better at understanding and communicating our effectiveness. Our Global Performance Framework was developed to help do this in a realistic, cost-effective, and credible way. Output data is aggregated annually under six thematic areas (humanitarian, resilience, livelihoods, women's empowerment, citizen voice, and policy influencing) to give us a sense of the scope and scale of our work. We then drill down and rigorously evaluate random samples of projects under each area in order to understand and evidence whether this work is resulting in positive change (known as effeciveness reviews). Now entering our third year, this presentation was a chance to share our experience and lessons learned to date.#InternalEvaluation #EvaluationPolicy #2013Conference #AdvocacyandPolicyChange #InternationalandCross-CulturalEval #OrganizationalLearningandEvalCapacityBuilding #EvaluationUse #Non-ProfitsandFoundationsEvaluation #DataVisualizationandReporting #ProgramTheoryandTheoryDrivenEvaluation #Cluster,Multi-SiteandMulti-LevelEval