... For this reason, a large body of research has attempted to investigate how students' background affects their achievement. This research has focused on students' socioeconomic status (Björklund & Salvanes, 2011;Nisbett, et al. 2012;OECD, 2019a;Sirin, 2005;Turkheimer, et al. 2003), the level of education of their parents (Black, Devereux & Salvanes, 2005;Burgess, 2016;Carneiro, Meghir & Parey, 2013;Chevalier, 2004;Holmlund, Lindahl & Plug, 2011;Oreopoulos, Page & Stevens, 2006), their immigration status (Akther & Robinson, 2014;Crosnoe & López Turley, 2011;OECD, 2016;OECD, 2019a, Tienda & Haskins, 2011, their age (Fredriksson & Öckert, 2005;Givord, 2020), their gender (Buser, Niederle & Oosterbeek, 2014;Buser, Peter & Wolter, 2017;Cai, et al. 2019;Griselda, 2020;OECD, 2004;OECD, 2019a;Ors, Palomino & Peyrache, 2013;Terrier, 2020), whether or not they have repeated a grade (Ikeda & García, 2004;Rumberger & Lim, 2008;Xia & Kirby, 2009), among other characteristics. ...