The Early Warning System (EWS) is a tool developed by the National High School Center to collect data on indicators including attendance, GPA, course failures and credits earned. These indicators have been found to be highly predictive of a student’s likelihood of dropping out of high school in large, urban areas. The EWS tool was studied in two suburban schools. With the exception of attendance data, findings suggest that the indicators and suggested threshold for risk determination are predictive in suburban contexts.
Johnson, Evelyn and Semmelroth, Carrie. (2010). "The Predictive Validity of the Early Warning System Tool". NASSP Bulletin, 94(2), 120-134. http://dx.doi.org/10.1177/0192636510380789