Federal law requires that state accountability systems include "another academic indicator" for elementary and middle schools in addition to academic achievement. Nearly all states use a measure of student longitudinal growth as their other academic indicator. But how should states decide which growth model to use? The Center for…

Education experiments frequently assign students to treatment or control conditions within schools. Longitudinal components added in these studies (e.g., students followed over time) allow researchers to assess treatment effects in average rates of change (e.g., linear or quadratic). We provide methods for a priori power analysis in three-level…

Economists often use test scores to measure a student's performance or an adult's human capital. These scores reflect non-trivial decisions about how to measure and scale student achievement, with important implications for secondary analyses. For example, the scores computed in several major testing regimes, including the National Assessment of…