This policy paper on social impact measurement for social enterprises was produced by the OECD and the European Commission. It presents the issues and ongoing debates surrounding social impact measurement and provides concrete examples of measurement methods. It highlights the concept of proportional measurement, in other words balancing up the costs and benefits of the measuring process. The policy brief also looks at guidance and resources for use by social enterprises and how to create a more widespread culture of measurement among stakeholders despite their often limited human and financial resources.