In Fall 2011, staff at the University of Minnesota Libraries-Twin Cities undertook a project to measure how often, and in what ways, students used the Libraries' services. Partnering with the University's Office of Institutional Research, the team investigated ways to match library service usage to individual accounts while retaining patron privacy to determine who was--and was not--using the library. With complete data sets, the group was able to determine overall usage rates for undergraduate and graduate students and compare how students in different colleges used library services. This article discusses data gathering techniques, analysis, and initial findings. (Contains 2 tables, 2 figures and 15 notes.)