KIPP's success has been achieved through a radically new approach to education. Old theories about the silver bullets of more money or smaller class sizes have been discarded in favour of a relentless focus on accountability and achievement. KIPP recruits elite teachers who work much longer days in a much longer school year (7.30am-5.30pm with a reduced summer holiday and regular Saturday school). In a symbol of their all-encompassing commitment, staff give pupils their mobile phone numbers in case they need any help with homework. 

Teachers are paid by performance (bonuses can be 10 per cent or more of salary), and action is taken rapidly if expected standards aren't met. Principals walk the corridors, entering lessons unannounced and asking to see lesson plans with no notice (in England headteachers in state schools are banned by union agreements from observing their teachers for more than three hours a year). This is all supported by professional and leadership training at the high-quality KIPP Foundation. 

The strong demands KIPP places on teachers are matched by its very high expectations of pupils. In a country where a young black man is more likely to go to prison than to college, KIPP's mainly black or Latino pupils are in year groups named after the year they will enter higher education, while teachers decorate their classrooms with banners from their own college days. Just in case pupils are in any doubt about expectations, motivational messages on classroom walls remind them. The most common reads: "THERE ARE NO EXCUSES." 

Excuses are also running out for those who defend a status quo in which the college completion rate for low-income pupils is just a quarter of that achieved by KIPP students. For decades the message from the education establishment was that until socioeconomic disadvantages were removed children from poor families were destined to fail. This was aptly termed "the soft bigotry of low expectations". KIPP, and other successful charters, have torpedoed this position with the hard facts of high attainment.