“This paper will demonstrate how to effectively measure the impact of a digital library and how this can enhance strategic planning. Measuring the impact of digital resources and how they affect the various benefitting communities improves evidence-based decision making. This paper will discuss how the recently developed Balanced Value Impact Model measures a digital resource by balancing both internal organizational and external community perspectives with social and economic considerations. This will be illustrated with research case studies from the Wellcome Library digitization programme and Europeana Impact Taskforce. The paper will further suggest means by which thinking about the value chain from activity, through output, to outcomes and impact can enhance strategic planning for digital libraries.”