Evaluating Growth for ELL Students: Implications for Accountability Policies

In recent years, many U.S. states have introduced growth models as part of their educational accountability systems. Although the validity of growth‐based accountability models has been evaluated for the general population, the impact of those models for English language learner (ELL) students, a growing segment of the student population, has not received sufficient attention. We evaluated three commonly used growth models: value tables or transition matrices, projection models, and student growth percentiles (SGP). The value table model identified more ELL students as on track to proficiency, but with lower accuracy for ELL students. The projection and SGP models were more accurate overall, but classified the fewest ELL students as on track and were less likely to identify ELL students who would later be proficient. We found that each model had significant trade‐offs in terms of the decisions made for ELL students. These findings should be replicated in additional state contexts and considered in the development of future growth‐based accountability policies.