The Every Student Succeeds Act (ESSA) requires states to identify high schools with a graduation rate less than 67% as low performing. Each low-performing high school is required to implement an evidenced-based strategy to improve student outcomes. One challenge that states face is identifying and selecting evidence-based practices supporting college and career readiness in high school. The College and Career Readiness and Success Center's Evidenced-Based Practices series highlights research-based practices that promote high school college and career readiness in snapshot, user-friendly briefs. This brief focuses on early warning indicators which are used to identify and intervene with students early to help them get back on track and meet major educational milestones, such as on-time graduation. Early warning system indicators are an evidence-based strategy available to struggling high schools.