Traditionally, libraries attempted to prove their effectiveness by reporting the number of resources the library bought or subscribed to, of instructional sessions taught and of reference questions answered, among other statistics. However, libraries are increasingly expected to document student achievement using outcomes assessment. After struggling with outcomes assessment at our own institution for several years, we have found that the most effective way to handle program-level and classroom-level outcomes assessment is to create manageable, realistic assessment tools. In this paper, we describe two assessment tools that have worked for us: a brief survey given to a large number of students and an in-depth, multipart tool used with a limited number of library instruction sessions.