Directorate for Education, Organisation de Coopération …; … - 2013
<UL> <LI>Successful education systems are able to guarantee that all students succeed at high levels. </LI> <LI>Across OECD countries, around 60% of the overall, country-level variation in student performance can be traced to differences in how well students who attend the same school can be expected to perform....</li></li></ul>