The International Initiative for Impact Evaluation (3ie) promotes evidence-informed equitable, inclusive and sustainable development. We support the generation and effective use of high-quality evidence to inform decision-making and improve the lives of people living in poverty in low-and middle-income countries. We provide guidance and support to produce, synthesise and quality assure evidence of what works, for whom, how, why and at what cost. 3ie evidence gap map reports 3ie evidence gap maps are thematic collections of information about impact evaluations or systematic reviews that measure the effects of international development policies and programmes. The maps provide a visual display of completed and ongoing systematic reviews and impact evaluations in a sector or sub-sector, structured around a framework of interventions and outcomes. The evidence gap map reports provide all the supporting documentation for the maps, including the background information for the theme of the map, the methods and results, protocols, and the analysis of results. About this evidence gap map report This report provides the supporting documentation for the 3ie evidence gap map on the effect of transparency and accountability interventions in the extractive sector, developed as a part of a project funded by the William and Flora Hewlett Foundation.