We are on the threshold of an analytics revolution. It has become essential for law librarians to understand the data we produce and the data that is used to describe and compare our institutions. Law librarians must be able to locate, analyze, and present data. This chapter will describe the major sources of data used for library administration, collection building, teaching and research, and law school administration. These sources can be used by law library directors to evaluate budgets, collections, services, facilities, staffing, and more. This chapter will also provide an overview of key statistical terms and concepts that all law librarians must know.