Over the past decade, research on dropout prevention has become focused on using evidence-based practice, and data-driven decisions, to mitigate students' dropping out of high school and instead, support and prepare students for career and college. Early warning systems or on-track indicators, in which readily available student-level data are used to predict whether a student is likely to drop out, are being harnessed by schools, districts, states, and support organizations nationwide to help prevent students from falling off the track to graduation and offer additional educational and support services to those who need them (Pinkus, 2008). Initiatives to create early warning systems are aligned with the What Works Clearinghouse Dropout Prevention Practice Guide recommendation that "utilizing data systems that support a realistic diagnosis of the number of students who dropout and that help identify individual students at high risk of dropping out" is a "critical first step" in effective intervention (Dynarski et al., 2008, p. 12). This paper provides information on K-12 early warning and success indicators. An annotated bibliography is included. (Contains 1 table and 1 footnote.)