In 2012, about 10% of the variance in mathematics score to PISA test was explained by the socio-economic background of students in Korea. On average across the OECD about 15% of the variance in PISA mathematics score is explained by socio-economic background reaching more than 15% in countries such as France and Germany. As in most other OECD countries, the variation in PISA mathematics score is higher within schools than between schools.