Responsible collection stewardship includes regular assessment of collection resources. This assessment should include, at a minimum, data from the following: academics & enrollment, acquisitions, circulation, interlibrary loan, and usage statistics. Collections-related data are currently collected in the UMass Amherst Libraries through various avenues and made available through Tableau software and other sources. However, there are no guidelines on how these data are used in decision making. This report will provide details of available data sources and make recommendations on how data can be used to inform collections decisions.