- The balance of evidence from the literature reviewed suggests the presence of school compositional effects.
- The best of British studies has reported a strong compositional effect in relation to English, and the most recent study of elementary school performance has also reported a compositional effect.
- From the US, the evidence has been stronger, although the familiar caveat in relation to American school effectiveness studies should be noted- their dependent variables are rarely exams that seek to test curriculum knowledge.
- The New Zeeland and Belgium studies all have limitations but also important strengths and these have pointed to the existence of school compositional effects as well.
- There is a need for better measures of school compositional effects and also to explore the processes that underlie them.