This technical report is one of a series of four technical reports that describe the results of a study comparing eight alternative models for estimating school academic achievement using data from the Arizona, North Carolina, Oregon, and Pennsylvania accountability systems. The purpose of these reports was to evaluate a broad range of models commonly used for estimating school performance that are applied in many states and frequently reported in the school effectiveness research literature. The introduction describes the study background and details the methods and procedures used to estimate the eight school performance models and compare model results in all four states. Details on each state's accountability data, assessment instruments, and results are included in their respective technical reports. The initial Oregon sample consisted of all students that took the Oregon Assessment of Knowledge and Skills (OAKS) mathematics (N = 483,502) or reading/language arts (N = 474,080) general assessment in any one school year from 2007-08 through 2011-12, and whose records in each year were included in the state calculation of Adequate Yearly Progress (AYP). The initial sample was separated into an elementary school sample (Grades 3 through 5) and a middle school sample (Grades 6 through 8), each consisting of three successive cohorts of students enrolled in school years: (a) 2007/08 through 2009/2010; (b) 2008/09 through 2010/11; and (c) 2009/10 through 2011/12. From elementary to middle school cohorts, there were small but consistent decreases in the proportion of English learners (EL), economically disadvantaged students (EDS), racial/ethnic minority students (i.e., American Indian/Alaskan Native, Asian/Pacific Islander, Black/African American, Hispanic, Multi-Ethnic, and Declined to report), and students with disabilities (SWD). At the elementary school level, almost 10% of the students were EL, almost 50% of the students were female, over 50% were EDS, approximately 33% were racial/ethnic minority students, and about 13% were SWD. Discussion of the study's results are organized into three sections: Section A describes school performance model estimates; Section B describes school ranks; and the appendices provide additional detailed results. [For the Arizona results, see ED585156. For the North Carolina results, see ED585157. For the Pennsylvania results, see ED585158.]