The District conducts a "cross-sectional" analysis of student dropouts annually; it examines dropout rates among students enrolled in various grades at one point in time. A "longitudinal" analysis, also conducted annually, tracks a group of students in the same grade or cohort over a period of several years. Each method addresses a different aspect of how many students are dropping out of school. This research brief provides information on the cross-sectional and longitudinal dropout rates and longitudinal graduation rates for 2009-2010. (Contains 7 tables.) [For the 2008-2009 edition of this report, see ED536604.]