At the same time, dropping out or repeating a grade can lead to premature withdrawal from school and lower employability of school leavers, causing a loss for educational systems in terms of social and financial resources, such as students’ learning, school buildings’ usage and teachers' work time (UNESCO International Bureau of Education, 1970(3]). Grade repetition, the practice of retaining students in the same grade, is used to give struggling students more time to master grade-appropriate content before moving on to the next grade (and prevent them from dropping out). Even if research finds that grade repetition can be ineffective in enhancing the achievement of low performers in the short run (OECD, 2016(4]), early retention may lead to better outcomes than late retention and retained students may catch up after several years (Fruehwirth, Navarro and Takahashi, 2016(si).