A compositional effect is when pupil attainment is associated with the characteristics of their peers, over and above their own individual characteristics. Pupils at academically selective schools, for example, tend to out-perform similar-ability pupils who are educated with mixed-ability peers. Previous methodological studies however have shown…

There is mounting evidence of substantial "teacher quality gaps" (TQGs) between advantaged and disadvantaged students, but practically no empirical evidence about their history. We use longitudinal data on public school students, teachers, and schools from two states--North Carolina and Washington--to provide a descriptive history of the…