in part this is the result of privatesubsidised schools setting admission requirements and selecting students based upon academic achievement or families socioeconomic background mineduc ace and es a practise being eliminated through the implementation of the inclusion law see chapter for example the difference between schools in the exposure to mathematics in chile as measured by pisa is the largest among all oecd countries when differences are analysed by schools socioeconomic status evidence shows that the proportion of qualified teachers in advantaged schools is higher than in disadvantaged schools vs oecd b