„In most countries, immigrant students reporting that the language used to administer the PISA assessment was different than the one they spoke at home had lower scores in reading than both native students and immigrant students who reported speaking the language of assessment at home, after accounting for mathematics scores and socio-economic status. On average across OECD countries, the gap in reading scores between native-speaking and non-native-speaking immigrant students was 16 points, but the difference can be much larger.“
OECD (Hrsg.), Changing the Odds for Vulnerable Children (2019), S. 37.