two widely used forms of stratification are grade repetition and early tracking while the decision to retain a student al a given grade or to place a student in a less academicallyoriented programme is made primarily on the basis of performance research suggests that students background characteristics can also play a role in the likelihood that students are sorted into different grades and programmes agasisti and cordero forthcoming van de werfhorsl and mijs volume ii provides a more indepth examination of the association between student performance and schoollevel resources learning environments and stratification policies and practices and of how they reflect the level of equity in a system