They were based on the international rankings of 15-year-olds using the OECD's Pisa tests.
Spieghalter added: "If Pisa measures anything, it is the ability to do Pisa tests.
British schools have had lacklustre results in the last two rounds of the OECD's PISA tests.
Italy does worse than anywhere else in western Europe in the OECD's PISA tests.
Behind the Pisa tests lies an ideology that accepts economic growth and competitiveness as the sole aims of schooling.
Pisa tests revealed Finnish pupils produced some of the world's highest scores in maths, science and reading.
When did Michael Gove find out about how England has fared in the latest round of Pisa tests?
Last month, the results of the most recent Programme for International Student Assessment, or PISA, tests were announced.
An outdated curriculum, especially in mathematics, shares much of the blame for the country's poor performance on PISA tests.
In 2012 their country came 56th among 65 in the OECD's PISA tests of competence in reading, maths and science.
Scotland marginally outperformed England in maths and reading on the last PISA tests, but fell behind on science.
