The OECD Programme for International Student Assessment (PISA) examines not just what students know in science, reading and mathematics, but what they can do with what they know.

Dou you want to know the results?

Here you are: in English, French or German.

Volume I:
http://www.oecd-ilibrary.org/education/pisa-2015-results-volume-i_9789264266490-en

Volume II:
http://www.oecd-ilibrary.org/education/pisa-2015-results-volume-ii_9789264267510-en