on average across oecd countries and after accounting for the socioeconomic profile of schools no association can be identified between the percentage of immigrant students attending a school and the likelihood that students attending that school will attain baseline levels of academic proficiency after accounting for schools socioeconomic profile a high concentration of immigrant students was associated with poorer performance in germany slovenia spain and switzerland slovenia was the only country where students who attend schools where more than one in four students has an immigrant background are less likely to attain baseline levels of proficiency after accounting for the school s socioeconomic profile