Schoeneberger, Jason A. The Clearing House: A Journal of Educational Strategies, Issues and Ideas, 85:1, 7-14. In this study, the researcher used longitudinal data on student attendance patterns from a large urban school district to model trajectories over time and categorize students into groups based on their attendance patterns from 1st through 8th grades. Using this technique, the study identified four categories of students: Constant Attendees who rarely missed more than 10% of school days; Developing Truants who showed increasing prevalence of absenteeism in the late elementary and middle school grades; Early Truants who were more likely to be chronically absent in the early elementary grades but showed improved attendance with time; and Chronic Truants, who exhibited the highest prevalence of missing school across all grades. Modeling each group’s trajectory, the study found that these longitudinal categories are predictive of high school dropout. Furthermore, while Chronic Truants have a 21% likelihood of dropping out, the likelihood for Developing Truants is even higher at 25%, suggesting that longitudinal attendance patterns should be used as a warning system to identify students at-risk of disengaging from school.