Growth models measure improvement by looking at how' a school has improved student performance independently of the level of achievement (Figlio and Loeb, 2011). Within each model, teachers are motivated to focus attention on different student groups. In status models, low-performing students receive greater attention to bring them up to proficiency levels, in growth models, teachers are rewarded for improving student outcomes for any level of student. Hence, in growth model systems teachers are less likely to exclude under-performing students, as any improvement in outcome is measured.