The authors analyzed the holdings, circulations, and interlibrary loan (ILL) borrowing requests of the English-language monograph collection at the University of Colorado at Boulder. Data for each area were mapped to conspectus subject areas, using Library of Congress Classifications, and then compared. The resulting data and subject distributions were analyzed by overall holdings, transactions per item, percentage of collection circulated, and a ratio of ILL holdings to requests. The method of analysis used in this study could be fruitfully applied to other research collections to assist with remote storage, preservation, and collection development decisions.n the current economic environment, it is critical for librarians to practice evidence-based decision making. With decreasing library budgets, especially for monographic materials, it also is essential for librarians to assess and manage collections to determine subject areas for acquisition, de-accession, digitization, preservation, and remote storage. One empirical collection assessment method is to examine usage statistics, such as circulation and interlibrary loan (ILL) data. Many librarians employ usage data as an indicator of the library's materials' relevance to user populations.Sonia Bodi and Katie Maier-O'Shea believe that librarians' knowledge of collections is often intuitive and urge librarians to make data-supported collection decisions. They suggest that collection development focus on learning outcomes of library users rather than on strictly comprehensive collections or even curriculum support.1 This approach is impossible without solid data from various perspectives.