This guidance document from the National Forum on Education Statistics provides an overview of early warning systems (EWS) from the perspective of the education data community. This resource supplies state education agency (SEA) staff with best practices in implementing an effective EWS to track and support at-risk students’ progression toward high school graduation. The guidance furnishes SEA staff with (a) an overview of an EWS and what to consider during the planning process; (b) a review of the EWS quality indicators, data considerations, analytics, and the continuous improvement process; (c) best practices in establishing and sustaining an EWS; and (d) case studies from selected state and district EWS. This resource includes a glossary of common terms, a list of related resources, and questions for consideration. The document also contains valuable appendices that encompass a checklist of tasks and activities in an EWS and an annotated list of quality indicators and data elements.