Chapter 1: Examining School Achievement Over Time: A Multilevel, Multiple-Group Approach

Implementing the requirements of new legislation to improve schools (e.g., No Child Left Behind Act of 2001)—in particular, the necessity of assessing students’ educational progress and then making judgments about school effectiveness—raises concerns about whether school comparisons are based on fair, accurate, and nondiscriminatory information to the fullest extent possible. By definition, effective schools should produce stable and consistent results over time that apply to all students within the school. Correctly modeling the school’s contribution to student achievement over time, however, has been problematic in previous research, especially when different groups of students are assessed on each measurement occasion. This chapter discusses these issues and presents results from a multilevel modeling approach researchers may use in monitoring changes in school achievement over time with successive cohorts of students.