This editorial article briefly examines the historical development of school effectiveness research (SER) and the importance of new methodological developments. It seeks to distinguish between school effects and schooling effects and introduces new topics, including regression discontinuity applied to cross-sectional data to identify the absolute effects of an additional year of schooling and the study of “seasonality” of learning through modelling students' term time progress compared with developments in summer recess. The value of growth curve modelling examining progress over multiple time points is explored. Potential problems in the use of SER data for accountability purposes are also examined. The value of studies focusing on non-academic as well as academic outcomes and the potential to explore in more detail differences in school effects for different student subgroups are also discussed and confirm that the field's strong roots in relation to the promotion of educational equity remain evident in more recent methodological approaches.