The OECD's PISA researchers conclude that the choices have little to do with ability and may well be influenced by ingrained stereotypes.

ECONOMIST: A world of bluestockings

The OECD Programme for International Student Assessment or Pisa tests examines the performance of 15-year-old pupils in mathematics, science, and reading.

BBC: OECD asked by Leighton Andrews for Wales education review

The reading abilities of German 15-year-olds, according to the PISA studies published by the OECD, are below the average for rich countries.

ECONOMIST: Education and skills

Dywedodd yr Athro David Egan o Athrofa Prifysgol Cymru Caerdydd (UWIC) fod perfformiad gwael Cymru yn yr OECD ar Rhaglen Ryngwladol Asesu Myfyrwyr (PISA) yn achos pryder.

BBC: Pwyllgor Plant a Phobl Ifanc

Professor David Egan of the University of Wales Institute Cardiff (UWIC) said that Wales' poor performance in the OECD's Programme for International Student Assessment (PISA) was cause for concern.

BBC: Children and Young People Committee

The influential Pisa test rankings, published by the OECD, put Massachusetts as the highest performing US state - but against a background in which the US has become an educational underachiever.

BBC: Massachusetts: Pioneering Gove's knowledge curriculum

In a PISA survey taken in the United States in 2009 by OECD, almost all students from the wealthiest backgrounds scored above minimum levels in mathematics.

UNESCO: Twenty percent of young New Yorkers out of school and out of work | United Nations Educational, Scientific and Cultural Organization

The first PISA study, in 2000, placed German pupils well below the OECD average for reading and literacy.

ECONOMIST: Reforming education

In the OECD's annual study of educational performance, the Programme for International Student Assessment (PISA), girls score better in reading in all countries even at primary level, and much better by the time they are 15.

ECONOMIST: A world of bluestockings