He has built a career jetting around the globe advising governments on how to improve their education systems. But now Sir Ken Robinson has criticised the world's most trusted league tables, which allow countries to compare their schools.
Sir Ken is one of the biggest names on the international education scene. He has written a New York Times best-seller and his work with governments in Asia, Europe and the US allows him to command five-figure sums for speaking commitments.
And yet the former professor of education at the University of Warwick in England has hit out at the hugely influential Programme for International Student Assessment (Pisa) for being too narrow in its focus.
Governments around the world are increasingly turning to the Pisa league tables to justify policy changes designed to raise standards, with ministers in England regularly using the country's modest standing in the maths, reading and science tests to justify reforms. But Sir Ken believes Pisa's focus on just three subjects is to the detriment of other, more creative areas, which are being "squeezed out".
In a video interview for the Core of Education website, the self-proclaimed champion of creativity in schools questioned whether governments were placing too much emphasis on international comparisons.
"Nowadays, countries tend to scrutinise each other's education policies like their defence policies," Sir Ken said in the interview, which took place ahead of the annual conference of leadership organisation ASCD in Los Angeles earlier this month. "I'm all for making sensible data available for people looking around at what other countries are doing. The trouble is these particular league tables are focused on a very narrow conception of education.
"It's mainly about literacy, numeracy and science, and of course these are very important. But the upshot is a lot of other very important areas of education, that matter just as much, are being squeezed out."
Sir Ken pointed to countries such as Finland, which performed very well in the Pisa tests but also "celebrated diversity, creativity and the importance of teachers".
"If you focus relentlessly on imposing a culture of standardisation then you may well get high results in the areas you focus on - that's been true of Shanghai, Singapore and Hong Kong - but you don't get the breadth of education all countries desperately need," he said.
Singapore is one example of a nation that has bought into Sir Ken's views, and it is in the process of overhauling its curriculum to place a greater emphasis on "holistic education" rather than just focusing on knowledge and skills. This is despite the city state regularly appearing near the top of the Pisa rankings.
It is not the first time the league tables have come under fire. Last year, TES revealed that academics were concerned that the data behind the tests was subject to "serious problems", while the techniques used to compile the rankings were described as "utterly wrong".
And just last month, former Australian prime minister Julia Gillard, who now chairs the Global Partnership for Education, warned that the tests were "pitched too high" for developing nations.
The Organisation for Economic Cooperation and Development, which runs Pisa, said it was already broadening the areas it assessed, with the most recent survey from 2012 quizzing 15-year-olds on creative problem-solving. The students were asked to tackle real-life challenges that could not be solved using routine solutions. The organisation is expected to reveal how individual countries performed over the coming weeks.
Sir Michael Barber, once an adviser to former UK prime minister Tony Blair and now chief education adviser at Pearson, said the move towards countries learning from one another was "very positive".
"Pisa has been a force for good in that regard, and has done well in testing the application and not just the acquiring of knowledge," Sir Michael said. "But Ken Robinson rightly points out that Pisa does not measure everything, and that is why it is really important not to focus purely on Pisa.
"We must beware of false dichotomies. Schools that do the best in academic achievements are generally the best in the arts and sports as well. You don't have to choose between the two."