Introducing market reforms to school systems leads to, at best, "very modest" gains and risks increasing the segregation of pupils by race, class and ability, a major international study has found.
The Organisation for Economic Co-operation and Development research is a potential embarrassment for the Government. It comes in the week that Education Secretary Michael Gove sought to promote his flagship "free schools" policy with a visit from Arne Duncan, the US education secretary, who has gone down a similar road by encouraging more charter schools.
But the OECD has looked at two decades' worth of academic studies on market reforms like charter schools, voucher programmes and the abolition of catchment areas and concluded that "the effects of market mechanisms in education are small, if they are found at all".
The OECD, representing 33 leading industrialised nations, also found "inconclusive" evidence that the reforms led to greater efficiency, as governments had hoped, and little to suggest they encouraged more innovation.
"In very general terms it seems that regimes providing parents with more choice bear a risk of increasing segregation between schools in terms of ethnic, socio-economic and ability segregation," the study* said.
"Compared with government aims when market mechanisms are introduced in education, and the fierce tone of the political as well as the academic debate on these issues, the effects as reported in empirical research are modest, to say the least."
Reports this week have also emphasised the coalition Government's intention to increase school choice by removing the limits that it says local councils impose to stop "good" schools from expanding to meet demand.
John Bangs, visiting professor at London Univesity's Institute of Education, said: "Despite all the sound and fury it seems that the weight of evidence is becoming overwhelming that it is what goes on in the classroom, not structural reform, that makes a difference. Given Michael Gove's enthusiasm for international evidence, this is one study that he really should take notice of."
The OECD identified market reforms that had taken place in schools systems from six continents. It said that most of the research it looked at had been conducted in the US, but the same conclusions held for studies in other countries.
The report suggests market reforms have had little effect because schools only compete with their near neighbours as parents need them to be within travelling distance.
Parental choice is also influenced by local hierarchies of schools that tend to place schools with able, white pupils from advantaged backgrounds on top, regardless of the quality of the education they offer.
The OECD also found that parents tended not to abandon schools even if they were underperforming.
* Markets in Education: an analytical review of empirical research on market mechanisms in education by Sietske Waslander, Cissy Pater and Maartje van der Weide
MEXICO - TOUGHER REGIME ADVISED
In an another report published this week, the OECD advises Mexico on how to improve its education system with a series of recommendations that it says can be applied to other countries.
To raise teacher quality it suggests improving the calibre of recruits by raising the bar for entry in initial teacher training colleges, improving the colleges and professional development, creating probationary periods for teachers and opening up all teaching posts to competition.
Measures to create better schools include creating school councils with real influence.