The full road to impact: the experience of the Global Environment Facility Fourth Overall Performance Study

The Evaluation Office of the Global Environment Facility (GEF) has developed an approach to impact evaluation that aims to go beyond causalities and counterfactuals into replication, up-scaling and longer-term lasting systemic changes. Starting from the OECD Development Assistance Committee glossary definition of impact and building on a theory-based approach to evaluation, several methods and tools have been developed that cover various aspects of the long road from outcomes to impact. This article presents both the development over time of these methods and tools and methodological considerations. Two full-scale impact evaluations were undertaken: the first on protected areas in Eastern Africa and the second on the GEF portfolio of projects supporting the removal from production and consumption of ozone-depleting substances in countries with economies in transition. In addition several other impact studies were undertaken. The evaluations of various aspects of the progress from outcome to impact were gathered and as far as possible aggregated in the Fourth Overall Performance Study of the GEF, which was presented in 2009 to the replenishment process of the GEF. An overview is presented of progress toward impact of the GEF portfolio of finished projects on climate change mitigation and on stemming the loss of biodiversity. The Office will continue to develop and use the variety of impact evaluation tools at its disposal.