How can the effectiveness of peacebuilding operations in countries marked by conflict be better measured? This policy brief examines the steps needed to improve the measurement of peacebuilding work, highlights the technical and political problems this work faces, and makes recommendations for action by organisations in the field. The experience of peacebuilding initiatives around the world has in recent years led to increased efforts to develop new and improved tools to measure their effects. Many projects are already underway, led by key civilian and military actors such as the United Nations itself to defence agencies, government departments, the World Bank, and NGOs. These various efforts reflect both the mismatch between ambitions and results in Afghanistan and Iraq and longer-term concerns about the limitations of data, methodology and practices in the area of measuring peacebuilding. There is a stark contrast here with development goals, where monitoring procedures are well established and far more data are available.