This manual has been produced to familiarize data users with the procedures followed for data collection and processing for the base year of the Education Longitudinal Study of 2002 (ELS:2002). It also provides the necessary documentation for use of the public-use data files, as they appear on the ELS:2002 base year Electronic Codebook (ECB). Most social scientists and policy analysts should find the data set organized and equipped in a manner that facilitates straightforward production of statistical summaries and analyses. This manual provides extensive documentation of the content of the data files and how to access and manipulate them. Chapter 1 serves as an introduction to ELS:2002. It includes an overview and history of the National Center for Education Statistics (NCES) program of longitudinal high school cohorts, summarizes the ELS:2002 objectives, and supplies an overview of the base year and longitudinal study design. Chapter 2 describes the data collection instruments, including both the development and content of the student, parent, school administrator, teacher, and library media center questionnaires, as well as the student assessments in reading and mathematics, and the facilities checklist. The sample design and weighting procedures used in the base year study are documented in chapter 3, as are weights, imputation, and the calculation of design effects. Data collection schedules, training, procedures, and results are presented in chapter 4. Chapter 5 describes data preparation and processing, including the receipt control system, optical scanning, machine editing, and data file preparation. Chapter 6 describes the contents of the data files, including the data structure and analysis populations. The appendices include, among other topics, an introduction to the public-use ECB (appendix A); the ELS:2002 questionnaires (appendix B); a glossary of special terms used in the ELS:2002 documentation (appendix E), and a crosswalk to the National EducationThis manual has been produced to familiarize data users with the procedures followed for data collection and processing for the base year of the Education Longitudinal Study of 2002 (ELS:2002). It also provides the necessary documentation for use of the public-use data files, as they appear on the ELS:2002 base year Electronic Codebook (ECB). Most social scientists and policy analysts should find the data set organized and equipped in a manner that facilitates straightforward production of statistical summaries and analyses. This manual provides extensive documentation of the content of the data files and how to access and manipulate them. Chapter 1 serves as an introduction to ELS:2002. It includes an overview and history of the National Center for Education Statistics (NCES) program of longitudinal high school cohorts, summarizes the ELS:2002 objectives, and supplies an overview of the base year and longitudinal study design. Chapter 2 describes the data collection instruments, including both the development and content of the student, parent, school administrator, teacher, and library media center questionnaires, as well as the student assessments in reading and mathematics, and the facilities checklist. The sample design and weighting procedures used in the base year study are documented in chapter 3, as are weights, imputation, and the calculation of design effects. Data collection schedules, training, procedures, and results are presented in chapter 4. Chapter 5 describes data preparation and processing, including the receipt control system, optical scanning, machine editing, and data file preparation. Chapter 6 describes the contents of the data files, including the data structure and analysis populations. The appendices include, among other topics, an introduction to the public-use ECB (appendix A); the ELS:2002 questionnaires (appendix B); a glossary of special terms used in the ELS:2002 documentation (appendix E), and a crosswalk to the National Education