Teachers in New York City are being pitted against each other, with the worst performers named and shamed.
The city's education department issued the so-called Teacher Data Reports last month, enabling media outlets such as The New York Times to publish the results. The reports grade nearly 18,000 of the city's 75,000 teachers, based on pupils' progress in standardised tests.
The system was developed five years ago as part of a pilot scheme under Joel Klein, the city's schools chancellor at the time. But plans to publish the ratings were vehemently opposed by New York's main teaching union, the United Federation of Teachers (UFT), which last month lost an 18-month-long legal battle to block the reports from being released.
UFT president Michael Mulgrew said the data on which the reports were based was "unreliable".
"We were angry about it, and felt we needed to do everything in our power to stop it from being released because we knew it was a research project," Mr Mulgrew said. "We also know that they stopped the project because the information they were getting was in no way reliable. This is bad data.
"We found out the Department of Education was mismanaging the process. We have hundreds of cases where teachers are having teacher data reports that have nothing to do with them; teachers telling us that `these were never my students; I taught a different grade level; I was on maternity' - that sort of thing."
It is unclear whether the education department will continue to publish teachers' ratings every year, but a similar scheme has taken place over the past two years in California, published by the Los Angeles Times (see panel).
In New York, the UFT has warned the media that it could take legal action if any article publishes "erroneous information", but the union now fears parents will push to have their children taught by one teacher over another.
The UFT has undertaken a "rigorous outreach programme" to parents, which involves a $100,000 (pound;64,000) newspaper advertising campaign including an open letter from Mr Mulgrew, under the headline "This is no way to treat a teacher".
A statement from New York City Mayor Michael Bloomberg said that the move to rank school staff fitted with his aim of attracting and rewarding "great teachers". "I made it clear that our kids could no longer tolerate having ineffective teachers in the classrooms and that it was critical to evaluate them fairly and quickly," he said.
"The system . will also help us ensure that teachers who are rated `ineffective' can be given the support they need to grow, or if that doesn't work, to be moved out of the classroom."
According to John Bangs, who sits on the trade union advisory committee of the Organisation for Economic Cooperation and Development, the plans to publish the data are at odds with the wider Obama administration's approach to teachers.
"President Obama has just launched a multi-million-dollar scheme called the Respect programme, which is a major project to improve the professional development of teachers," Mr Bangs said. "It seems to me that Mayor Michael Bloomberg and New York City's approach of punishing teachers is in total contradiction to what Barack Obama is doing nationally."
WHAT'S THERE TO HIDE?
The Los Angeles Times first published the rankings of more than 6,000 elementary school teachers, based on their abilities to improve pupils' scores on standardised tests, in 2010.
The newspaper obtained seven years of maths and English scores from almost 1,100 schools and adult education centres. Arne Duncan, the US education secretary, said at the time that he supported publication. "What's there to hide?" he told the paper.