The quantity and quality of resources available to schools improved significantly between 2003 and 2012, on average across OECD countries. Greater financial investments in education provided schools with better teaching staff, instructional materials and physical infrastructure. The learning environment in schools across OECD countries improved between 2003 and 2012, particularly when it comes to teacher-student relations and the proportion of students who arrive late for school. The degree to which students from different socio-economic backgrounds attend the same school did not change between 2003 and 2012, while students with different academic abilities and needs were less likely to attend the same school in 2012 than in 2003, on average across OECD countries.