Is a Good Teacher a Good Teacher for All?

Districts, states and researchers are using value-added models with increasing frequency to evaluate educational policies and programs, as well as teachers and other educators individually. Despite their prevalence, little research assesses whether value-added measures (VAM) are consistent across student subgroups. Are teachers who are effective with one group of students also effective with others? If they are not, then it may be worthwhile to develop separate measures of teacher effectiveness for different student groups; if they are, a single, average measure will likely suffice. Our paper uses data from a large, urban district with a considerable English learner (EL) population to compare teachers’ VAM with ELs to the same teachers’ VAM with non-ELs. We find that teachers who are effective with ELs also tend to be effective with their non-ELs and vice-versa. We also, however, find evidence that some teachers are relatively more effective with ELs than with non-ELs, and that this increased efficacy is predicted by a teacher’s fluency in students’ home language and whether he or she possesses a bilingual teaching certification.