Scale-up is the practice of introducing proven interventions into new settings with the goal of producing similarly positive effects in larger, more diverse populations. Scale-up research examines factors that influence the effectiveness of interventions as they are brought to scale across settings. This article has three objectives. First, it defines the goals of scale-up research with respect to broader efforts to enhance the quality of educational research and promote evidencebased education. Second, it clarifies the importance of context, conceptually and methodologically, in conducting scale-up research.Finally, it suggests practical guidelines that can assist researchers in developing designs that can be implemented in field settings to produce robust, generalizable findings.

English This article compares the International Baccalaureate Primary Years Programme (IBPYP) as implemented at three schools in the USA. The author hypothesizes that the schools each offer a unique form of the program based on the respective context and capacity to implement the IBPYP. The author found consistency among the faculties in their explanation of key components of the program. Variation existed in the implementation of these concepts. The author concludes that this variation is due to the different contexts of implementation and to the ambiguity inherent in the IBPYP. French Cette étude compare la mise en oeuvre du Programme primaire (PP) de l'Organisation du Baccalauréat International (IBO) dans trois établissements scolaires aux États-Unis. L'auteur émet l'hypothèse que chacun d'eux propose une forme unique de ce programme basée sur leur contexte respectif et leur capacité à le mettre en oeuvre. L'auteur a découvert une certaine cohérence dans les explications que le corps enseignant de chacun de ces établissements donnait des éléments clés du programme. Il existait toutefois des différences dans la mise en oeuvre de ces concepts. L'auteur conclut que ces variations sont dues aux différents contextes de mise en oeuvre et à l'ambiguïté inhérente au PP. Spanish Este estudio compara cómo tres colegios en Estados Unidos implementan el Programa de la Escuela Primaria (PEP) de la Organización del Bachillerato Internacional. La hipótesis del autor es que cada colegio tiene una forma propia y única de ofrecer el programa, en función de su contexto y de su capacidad. El autor observó coherencia en la explicación de los componentes clave del programa dada por los docentes de los tres colegios. También observó diferencias en su implementación de estos conceptos. El autor concluye que estas diferencias se deben a los distintos contextos de implementación y a la ambigu¨edad inherente al PEP.