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 often confusion about distinctions between growth models and value-added models. The first half of this paper attempts to dispel some of these confusions by clarifying terminology and illustrating by example how the results from a large-scale assessment can and will be used to make inferences about student growth and the value-added…