NEW YORK (CBSNewYork) -- The city education department released the ratings on thousands of public school teachers on Friday after a bitter legal battle.
The Teacher Data Reports grade teachers based on how much progress their students have made on standardized tests. But angry instructors say the numbers do not tell the entire story and are not an accurate representation of their effectiveness.
The data covers 18,000 math and English teachers from fourth through eighth grades over a three-year period from 2007 to 2010. The reports are based on how well a teachers' students score on state tests, with a complicated "added value" formula.
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The United Federation of Teachers had been waging a legal battle to keep the names confidential. However, the data was unsealed after a freedom of information court battle that lasted a year and a half.
Teachers argue the numbers are not a true representation of the classroom. They argue any good teacher wants to be evaluated, but not with what they believe is fuzzy math and shoddy data.
On his weekly radio show, Mayor Michael Bloomberg addressed the topic.
"The bottom line here is we have data, you want to have data, you need the data and the courts said it's owned by the public and you have to give it to them," Bloomberg said.
The mayor added that the city wants every teacher to succeed.
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"They have to produce and educate our kids, if they're not, you don't want to get rid of them you want to help them get the training they need so that they can do the job," Bloomberg said. "If they can't, then there's no question what you have to do. The school system should be run for our kids and you cannot leave kids in front of a teacher that is not doing the job."
Brooklyn teacher Marie Kallo is not happy, even though her ranking is well above average.
"Even though I received a pretty good rating, it makes me question the validity of it because the number of students weren't represented accurately," she told CBS 2's Dave Carlin.
Kallo says her total student count was off by about a hundred kids.
The teachers union launched a newspaper ad campaign on Friday titled "This Is No Way to Rate a Teacher" blasting the ratings formula. The union argues the formula is inaccurate and based on tests that were discredited after the education department said the exams had become too easy to pass.
They call the ratings flawed and misleading.
"The mayor's education legacy is in shambles, maybe they're trying to say, 'Oh, let's just try to do the teacher bashing routine so nobody realizes what we've done to the school,'" union president Michael Mulgrew said, blasting the Bloomberg administration.
"I have not met anyone that thinks this was a great idea," said NYU economist Sean Corcoran, who analyzed the complicated test score-based rating system for the education department and says parents should know the margin for error can be something like 60 percent.
"They should take it with a huge grain of salt. This is just one piece of information that's not a very informative piece of information without a lot of other contexts," he told WCBS 880 reporter Alex Silverman on Friday.
"For the vast majority of teachers, we don't learn much more from these other than that they're no different than the average teacher," Corcoran added.
Jose Vilson, who teaches 8th grade math in Washington Heights, say parents don't need numbers.
"Think about whether their child actually likes the teacher," he said. "More often [than] not teachers have shown that students are a better measure."
Vilson has no doubt some of his colleagues will be unfairly judged.
"I think there will be less and less people actually wanting to become teachers," he said.
Schools chancellor Dennis Walcott calls it irresponsible for anyone to use these numbers to judge individual teachers.
Charter school and special education teachers were not included. Those findings will be released next week.
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