Now that all 50 states and the District of Columbia are building statewide longitudinal data systems, the next step is to ensure that the information in these systems is used to improve student learning. The Data Quality Campaign (DQC) has identified 10 actions that states can take to ensure that the right data are available and accessible and that users have the knowledge and skills to use the data well (see "10 State Actions To Ensure Effective Data Use," page 2). This paper discusses reports that states can create using longitudinal data. These reports include, but are not limited to: (1) Growth reports looking at changes in the achievement of the same students over time; (2) Diagnostic reports providing academic histories of students' mastery of specific concepts or skills; (3) Early warning reports identifying students who need immediate help based on at-risk indicators; (4) Predictive reports showing the relationship between earlier and later student outcomes--for example, the relationship between 8th grade test scores and students' readiness for college and careers in 12th grade; (5) Cohort graduation reports showing graduation rates of groups of the same students followed since the beginning of 9th grade; and (6) Feedback reports providing information on outcomes for students after they graduate from a school or district. (Contains 3 tables, 10 figures, 16 resources and 20 endnotes.)