Impact: the last frontier in digital library evaluation

The NSF-funded National Science Digital Library (NSDL) is engaged in an ongoing discourse about digital library evaluation. The Educational Impact and Evaluation Standing Committee (EIESC) has successfully identified desirable features in digital libraries such as usability and usage, but the hardest measure is impact. What is the impact of a DL? Members of the EIESC have engaged in pilots and feasibility studies using bricolage (a blend of qualitative and quantitative approaches to evaluation), and these activities are moving NSDL toward a richer understanding of impact