Using data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K), AIR described the middle school experiences of the cohort. The ECLS-K followed the educational, socioemotional, and physical development of a nationally representative sample of kindergartners in public and private schools in the United States from the fall of 1998 through the spring of 2007.

Information was collected from the children, their parents, their teachers, and school administrators. The ECLS-K represents nearly four million children who attended kindergarten in the United States in the 1998-99 school year, or attended first grade in the United States in the 1999-2000 school year. The Eighth Grade: First Findings From the Final Round of the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K) report used data collected from the final round of the ECLS-K, when most of the cohort (87%) was in the eighth grade, and provides information about their academic achievement, school activities, and educational aspirations.

This project provided a snapshot of the eighth-grade round of the ECLS-K and made the data available to encourage further in-depth analysis of the data using more sophisticated statistical methods. It focused on multiple aspects of the cohort's middle-school years in the spring of the 2007, including reading, math, and science achievement, school-sponsored activities, homework, and educational aspirations.