Countries such as the UK and the US are not being "remotely bold enough" and "fear risk-taking" when effecting change in their school systems, one of the world's best known education reformers has said.
Joel Klein, former chancellor of New York City's schools, added that officials should not be afraid to innovate, even if a system were "working perfectly". He urged an audience of school leaders, teachers and policymakers to go further with their reform agenda in order to properly prepare children for the world of work in the 21st century.
While making his call for more audacious reforms, Mr Klein praised England's education secretary Michael Gove, saying that he had challenged the status quo "with panache".
His comments came as many educationalists in the UK and across the pond have decried the pace of school reforms, calling for politicians to intervene less in state education rather than more.
Mr Klein, who ran New York's schools from 2002 to 2011, also warned the city's newly elected mayor, Bill de Blasio, not to exclude independent, state-funded charter schools from his education agenda, arguing that they had proved popular and successful.
As chancellor, the former lawyer oversaw one of the most aggressive reform agendas in the US public school system, closing down scores of local government-controlled district schools and replacing them with charters. He also introduced controversial report cards to grade individual schools and pared back teachers' rights.
But speaking in London last week, Mr Klein said that he did not go far enough during his period in charge of New York's 2,000 schools, particularly when it came to creating a more "professionalised" teaching workforce that was subject to performance-related pay.
"The problem with education reform is that we're not being remotely bold enough," he said. "One of the things I kept finding (on visits to other US school systems), whether it was New York, (Washington) DC or wherever, no matter what we were doing we all came away with a deep feeling that we were not being bold enough, not just in our thinking but in our execution."
Those working in school systems needed to be fearless innovators, he said, adding that even if the system were functioning well "we would still want to innovate".
"And we are far from perfect and yet we fear innovation, we fear risk-taking, we are afraid to try new and different things," he said.
Mr Klein, who is now chief executive of Amplify, the education arm of Rupert Murdoch's News Corp, hailed the reform agenda in England led by Mr Gove. The education secretary - a self-professed fan of many US education reforms - has become a controversial figure thanks to his fast-paced changes to school structures and teachers' pay and conditions.
"What I have found in New York City is that too many people defend the status quo because it works to serve interests that are not necessarily in the interest of the students, and I think Michael (Gove) has taken that on boldly and with panache," Mr Klein said.
But his comments were heavily criticised by Mary Bousted, general secretary of the UK's Association of Teachers and Lecturers, who warned Mr Gove against adopting policies from across the Atlantic.
"Joel Klein needs to look very closely at what's happening in the US with performance-related pay and the hire-and-fire culture they have, because it is not raising standards," Dr Bousted said. "We do not need to look to the US for this type of inspiration. We do not need a US curriculum, we do not need to look to the US for teaching and learning practices and we certainly don't need the US performance-related pay system."
But not everyone in the UK sector disagrees with Mr Klein. Jonathan Simons, head of education at thinktank Policy Exchange, said that more work needed to be done on the professionalism of the teaching workforce. "Part of that is met with performance-related pay," he added.
One of Mr Klein's most controversial reforms in New York was allowing charter schools to open on the same site as existing district schools. This is now being actively challenged by Mr de Blasio, who swept to victory in the city's mayoral election after promising to concentrate on improving district schools rather than opening more charters.
In his campaign, Mr de Blasio pledged to impose a year-long moratorium on charter schools opening on the same site as public schools. He has also vowed to charge rent to the dozens of charters that have already done so, potentially stripping millions of dollars from their budgets.