But that doesn't mean we have nothing to learn from America's experiments. The latest US rsearch (pages 11 and 27) suggests that phonics instruction, small classes, innovative academic calendars and longer school days have an especially beneficial effect on deprived youngsters. However, it is extra tests and school accountability measures that are now on offer in most US states.
This is an understandable response to decades of public school underachievement. But it is hard to see how more tests can prevent young people from ending up begging on the streets of Seattle - or London.