Shanghai has won acclaim for repeatedly topping global education league tables. But the Chinese city is now considering pulling out of the Programme for International Student Assessment (Pisa) because of fears that the tests are stifling wider reforms.
The Shanghai Education Commission has yet to decide whether it will take part in Pisa in 2015, despite the city being ranked as the best-performing region in the world in the last two rounds of tests.
Shanghai's withdrawal would be hugely damaging to Pisa, which has become increasingly influential in recent years. Many nations have used the league tables to drive changes to their own education systems.
Andreas Schleicher, deputy education director at the Organisation for Economic Cooperation and Development (OECD), which runs Pisa, has argued vehemently that Shanghai's achievements are not down to "drilling" students and cannot be explained by rote-learning stereotypes.
But according to Xinmin Wanbao, a state-run daily newspaper in Shanghai, the city is "considering withdrawing" from Pisa because it believes that its position at the top of the league tables masks shortcomings in its schools.
Yi Houqin, an official within the Shanghai Education Commission, told the paper: "Shanghai does not need so-called `number one schools'. What it needs are schools that follow sound educational principles, respect principles of students' physical and psychological development and lay a solid foundation for students' lifelong development."
One of the factors under consideration is the amount of time students are spending preparing for tests and doing homework, he added. Teachers, too, are devoting between two and five hours every day to "designing, reviewing, analysing and discussing homework assignments".
The OECD told TES that it was "still in discussion" with the Shanghai authorities about participation in the next round of Pisa. However, the organisation has already published a list of regions that have signed up for the 2015 tests, which includes other top performers such as South Korea, Finland, Singapore, Hong Kong and Macao.
An OECD spokesman said: "To date the [Shanghai] officials with whom we have had contact have found it useful to take part in Pisa to learn from other education systems."
The British government has talked about the need to emulate Shanghai's success, especially in maths. Education minister Elizabeth Truss led a delegation to the city in February to strike a deal that will bring teachers from Shanghai to England.
But John Bangs, chair of the OECD Trade Union Advisory Committee's working group on education, said that Shanghai's withdrawal would be a "body blow" for Pisa, given the OECD's praise of the city. He also said that it could force a rethink of the league tables.
"The OECD says league tables are just 5 per cent of what Pisa is about, but the tables are what every country buys into," he explained. "If Shanghai did pull out, it would be the first time the league tables have turned around and bitten their creator. Pisa needs an alternative to the league table approach as they have become a juggernaut."
Yong Zhao, associate dean for global education at the University of Oregon's College of Education in the US, who has long been a critic of Pisa, said the tests were getting in the way of Chinese education reforms.
"China is launching a new high school curriculum next year," he said. "They have been changing the curriculum for a long time. The basic thing is the Chinese do not believe Pisa means that much and, actually, they felt it was trying to narrow what they are trying to expand."
Michael O'Sullivan, chief executive of Cambridge International Examinations and former secretary general of the EU Chamber of Commerce in China, said Shanghai was "intent on serious reforms" in its schools.
"[Officials] are concerned about hothousing and the number of hours their students are spending on education, and the impact that is having on child development," he said. "They are also concerned their system allows for very little choice. Its main exam, the college entrance exam - the gaokao - focuses on the scientifically and mathematically inclined, leading other students to be deemed as second rate."
Sweeping curriculum reforms are already under way in Singapore, another top-performing Pisa region, which is moving its focus from "academic education" to the "holistic development of the child".
Dr Yong Zhao, associate dean for global education at the University of Oregon's College of Education, will be speaking at the Inspiring Leadership conference in Birmingham on 11-13 June.
Organised by the Association of School and College Leaders, the NAHT headteachers' union and the CfBT Education Trust, with TES as media partner, the conference is designed to replace the National College's Seizing Success event. Other speakers include the man behind the Pisa rankings, Andreas Schleicher, and World Cup-winning rugby coach Sir Clive Woodward.