Oxford University Library Services (OULS) is using Ulrich's Serials Analysis System (USAS) to manage and rationalize periodical holdings across 36 libraries. With the exact level of duplication having been identified through USAS, OULS has access to a range of reports and analyses which have been utilized in a variety of ways. This article explores some of the main practical purposes which USAS has served at Oxford. It shows how the system can be used in conjunction with an electronic database of library holdings in order to create increasingly versatile reports. Although USAS has flaws, its main strength is its ability to process large amounts of data and present output in a very usable format. The fact that this automatic output still needs manual manipulation does not alter the system's essential efficiency.