Results of the OECD Programme for International Student Assessment (PISA) show that participation in ECEC is strongly associated with better reading performance at age 15, even after accounting for students' socio-economic background. In 2012, on average across OECD countries, 41% of students with no pre-primary education performed below the baseline proficiency level in mathematics, compared to 30% of students who had attended pre-primary education for less than a year and 20% of students who had attended pre-primary education for more than a year. The difference in the share of low performers between students with no pre-primary education and students with more than a year of pre-primary education is statistically significant in all EU22 countries1 except Estonia, Ireland and Latvia.