“…The school influences the performance of its students from the first years of schooling (Ferrão, 2014). There are centres that have a high added value, regardless of the socioeconomic context in which they are inserted (Azpillaga et al, 2014;Cohodes, 2014;Ferrão, 2014;Gamazo et al, 2017;Intxausti et al, 2016Intxausti et al, , 2017Jennings et al, 2015;Joaristi et al, 2014;Lizasoain et al, 2016;Martínez et al, 2017;Rutledge et al, 2015). Therefore, educational research should focus its efforts on studying the school variables that affect educational performance (Ferrão, 2014;Joaristi et al, 2014) which cannot always be done in a quantitative way (Fuller & Hollingworth, 2014).…”