The Size of School Effects Compared to Teacher Effects: An Overview of the Research Literature

If one takes the variance between grades (in primary education) or subjects (in secondary education) as an indicator of teacher effects within schools, the conclusion that teacher effects dominate over school effects seems inevitable. Comparisons between parallel classes within schools should be considered more valid, but these studies fail to provide clear support for the supposition that teacher effects outweigh school effects. In any case, they suggest that the dominance of teacher effects is not inevitable.