Even more concerning, levels of socio-economic inequity have not changed since 2006 in the majority of countries. Figure 3 shows that in a few countries, such as Australia, Finland and Korea, the discrepancy between students in the top and bottom quartiles of PISA’s socio-economic ESCS index grew even larger between 2006 and 2015. However, PISA results show that inequality of opportunity is not set in stone, and that selected school systems succeeded in becoming more equitable over a relatively short period (OECD, 2017(8]).