“…The policy of grouping students born up to one year apart in the same class, based on an arbitrary cutoff date, is widespread in OECD countries but costly in terms of human capital formation. Indeed, scholars have shown that the youngest pupils in a class are more likely to suffer from grade retention, to be assigned to remedial classes, to receive lower grades, to be retained, and to skip lessons (Peña, 2016;Liu & Li, 2016;Navarro et al, 2015;Ponzo & Scoppa, 2014;Sprietsma, 2010;Elder & Lubotsky, 2009;Bedard & Dhuey, 2006). These performance gaps are also known as relative age effects (RAEs;Allen & Barnsley, 1993).…”