Abstract
Scaling up educational interventions remains a central yet under-theorised challenge in educational research. Although conceptual frameworks outline principles for successful scale-up, evidence on how scaling is operationalised in practice has not been systematically synthesised. This systematic mapping review synthesises 79 empirical studies of scaled-up educational interventions. Using a configurative approach, we developed and iteratively refined a coding scheme to identify and organise observable features employed during scale-up. The analysis generated a comprehensive feature map, comprising three broad dimensions (Instructor training, Intervention delivery and Intervention sustainability) and a set of sub-features within each. Descriptive and exploratory analyses examined patterns in feature prevalence across domains, educational settings and reported effect sizes. The findings reveal substantial heterogeneity in scale-up design across studies. By clarifying how scale-up has been enacted across diverse contexts, this review contributes an empirically grounded feature map for analysing scale-up design and provides a foundation for future comparative and implementation-focused research.