As such, equity should be one of the key objectives in any strategy to improve an education system. For example, disadvantaged students (those in the bottom quarter on the PISA index of economic, social and cultural status within their countries/economies) score 88 points lower in science than advantaged students (those in the top quarter on the index), on average across OECD countries. In B-S-J-G (China), Belgium, CABA (Argentina), France, Hungary, Luxembourg, Malta and Singapore, the difference ranges between 110 and 125 score points (Table 1.6.3a).