Before you were born, you may have already taken a test (a prenatal test). You likely have been tested repeatedly since then, with the results of many of those tests having meaningful consequences in your life. This chapter focuses on the use of tests and test scores relevant to employment selection settings. Personnel selection is only part of a system of practices that, together, contribute toward meeting a variety of organizational goals (e.g., improved job performance, more effective teamwork, improved learning outcomes, higher motivation, reduced turnover). In other words, an organizational problem with any complexity to it is usually not purely a “selection problem,” meaning that it is most effectively evaluated and addressed through an integrated approach to practice that involves a broad set of professional, strategic, and technical skills (Huselid, Jackson, & Schuler, 1997). Just as selection systems do not exist in isolation, neither do selection test scores. Decisions about the type of test scores to collect might be influenced by a number of considerations, such as the type of training that will or will not be provided to job applicants once they are selected; the knowledge, skills, abilities, and other characteristics (KSAOs) of applicants who are the focus of the organization’s recruiting strategies; or the time and budget available for test administration. Because of the broad context of selection systems and testing, selection researchers and practitioners can meaningfully improve their skills and their work by remaining connected with the literature in training, motivation, leadership, teamwork, technology, and other relevant substantive areas outside of their usual niche.