This report uses administrative data provided by the Los Angeles Unified School District (LAUSD) on kindergarten to third-grade students. The records begin with kindergartners in 2001, first-graders in 2002, second-graders in 2003, and third-graders in 2004 and include all LAUSD students in grades K-3 for 2004 to 2008. Altogether, the raw data file has grade promotion information on over 490,000 students in just over 500 schools between 2001 and 2008. The authors complement the LAUSD data with several school-level variables from the California Department of Education (CDE) for 2001 to 2008. Specifically, they use the Academic Performance Index (API) data file and the California Basic Education Data System (CBEDS) to construct measures of school performance, enrollment, and teacher characteristics. Appendices include: (1) Data Description; (2) Study Methods; and (3) Regression Results. (Contains 8 tables and 7 footnotes.) [This research was conducted with support from Karina Jaquet. For the main report, "Early Grade Retention and Student Success: Evidence from Los Angeles," see ED517457.]