As a result, the socio-economic differences across schools are largely predictive of a school’s performance in the OECD PISA assessments. Policies that target disadvantaged schools, but also disadvantaged students, can therefore be particularly effective in raising performance and equity levels. Grade repetition is frequent, and this has proven an ineffective way to support poorly performing students. Around one third of students had repeated grades at least once by age 15 in 2012.