cahlan edison elementary school is a 20 minute drive from the dazzling casinos of central Las Vegas. The drab single-storey buildings in a poor suburban area could not look more different from their brash neighbours. But the casinos and the school open their doors for the same reason: to make money.

Cahlan is one of six elementary schools in Las Vegas run by Edison Schools, the biggest for-profit operator of US state schools.

The company runs around 100 schools in 20 states. It opened its UK office five years ago and now works as a consultant to more than 50 primary, secondary and special schools. Earlier this year it took over the entire management of a London comprehensive in a pound;1 million deal. (See below)

While Edison can claim success in improving results in some of its US schools, in others progress has been slow and contracts have been cancelled. A junior school in Las Vegas went back to public ownership after it was decided pupils could not cope with Edison’s high-pressure testing regime.

The company took over the running of Cahlan elementary in 2001 as it languished near the bottom of Nevada’s state league tables. It hasturned the school into one of its biggest success stories.

In 2004, Cahlan was named the most improved school in the district, rocketing from around 300th in the tables to the top 20.

Edison provided new text books, teacher training and more than 300 computers. The school day has been extended by 90 minutes and Saturday catch-up classes were introduced to help struggling pupils.

he new regime also included one of the most controversial parts of the Edison approach, a regimented series of monthly tests known as benchmarks.

All pupils sit computerised tests in reading, maths and English comprehension. Their results are posted on the backs of their chairs, as well as on the door of every classroom. Teachers are given extensive training in data analysis so they are able to produce graphs measuring all aspects of their pupils’ performance.

“It seems like a lot of testing, but we use it to focus our teaching,” said Sarah Popek, a senior teacher. “When we started doing data analysis, I thought it was all too much. But when I saw the benefits for my students, I bought into it.”

All Edison’s US contracts are based on performance-related pay, measured by results or attendance, whatever a school aims to improve.

Cahlan is one of many in Las Vegas open year-round to cope with the rapidly growing population in the city. Almost 90 per cent of its pupils come from Hispanic families and many do not speak any English, but that does not excuse them from sitting the tests.

Dr Jean Jackson, Cahlan’s principal, said she petitioned to get Edison because of the extra money and resources to improve the school.

“We were under-performing and had been for many years,” she said. “We wanted Edison. They did not buy us, we bought them.”

The company enjoyed considerable success on the US stock market during the 1990s, but has recently been taken back into private ownership after its shares plummeted.

* Teachers TV is screening a series about the American education system. The latest in the series, Land of Opportunity, can be seen tomorrow at midday on Freeview and at 7.30pm on Sky, Virgin and Tiscali TV.