the second section focuses on variations within countries and across time and explores how changes in studentteacher ratios class size teacher compensation and school autonomy for selecting teachers are related to performance trends across all pisaparticipating countries and economies the last section focuses on variations within countries and explores how teachers qualifications and experience teacher turnover and support for teachers professional learning are related to schoollevel outcomes the use of such data by the oecd is without prejudice to the status of the golan heights east jerusalem and israeli settlements in the west bank under the terms of international law