Both the Association of College and Research Libraries (ACRL) and the Public Library Association (PLA) provide important data services. For library managers and administrators, the key to the data's usefulness is knowing how to extract and apply the most relevant information to managing a library and improving accountability. A companion volume to the authors' earlier book Getting Started with Evaluation, this guide illustrates how to use the data to support value, collection use, benchmarking, and other best practices.