NEW YORK — A New York Supreme Court judge will decide whether the public has a right to see individual teacher ratings based on student test scores in the nation's largest school district, an indication that the days when 99 percent of teachers were rated "satisfactory" are over.

Arguments before the court will be held Nov. 24, and they'll come at a time of intense national interest in finding better ways to judge the effectiveness of teachers. Regardless of what the court decides, the idea of holding teachers accountable for student performance seems here to stay.

Nationally, many teacher evaluations already take into account how much students learn, and school districts across the U.S. soon could be required to make similar disclosures of teacher ratings. The push comes after the Obama administration insisted that states that are competing for grants in its $4.3 billion Race to the Top program find ways to link student performance to teacher evaluations. Twenty-five states now have policies that permit this, and hundreds of school districts are using these so-called value-added models to crunch the numbers.

"Value-added" ratings use complex statistical models to project a student's future gains based on his or her past performance. The idea is that good teachers add value by helping students progress further than expected, and bad teachers subtract value by slowing down their students.

New York City's Department of Education thinks that the public has a right to view the ratings of the city's 12,000 public elementary and middle school math and English teachers — the groups and subjects in which students take state standardized tests — along with their names and schools. The United Federation of Teachers sued Thursday to block the move, however, calling the ratings unreliable and the methodology that's used to calculate them unproven.

The city agreed not to release the names for now, pending next month's hearings.

Releasing teachers' names and ratings, the union's petition to the court says, could damage the professional reputations of thousands of public school teachers irreparably. New York media organizations have sought the data in the wake of the precedent set by the Los Angeles Times, which this summer created a publicly accessible database of teacher ratings.

Natalie Ravitz, a spokeswoman for New York City schools Chancellor Joel Klein, said the data were indicators of teachers' effectiveness, and that releasing the information was in the public interest.

"Value-added data doesn't tell the whole story of a teacher," Ravitz said in a statement. "But when teachers consistently perform at the top or the bottom, year after year, that is surely important. ... These are public schools and public tax dollars."

Rob Weil, the deputy director for educational issues at the American Federation of Teachers, disagreed, saying that while the union is looking for better ways of evaluating teachers, test scores aren't enough.

"We agree that there need to be better ways of evaluating teachers, but these scores are not a good measure. They are not fair, they are not adequate and they are not accurate," Weil said.

Dan Weisberg, general counsel of The New Teacher Project, a national nonprofit organization that's advocated overhauling teacher evaluations to improve student learning, said there was new momentum for change.

"Districts and unions also need to work together to provide parents with more and better information about teacher effectiveness; if not individual ratings, then at least school-level statistics, as teachers are the most powerful school-based factor in student academic success or failure," he said.

Using value-added models to calculate teacher effectiveness wasn't possible on a wide scale until recently. In the 1990s, William L. Sanders, a statistician at the University of Tennessee, pioneered the technique with student test scores. The method — as Sanders puts it — is like measuring a child's height on a wall. It tracks a child's academic growth over the year, no matter how far ahead or behind the child was initially. Sanders discovered that teacher quality varied greatly in every school, and he found that students assigned to good teachers for three consecutive years tended to make great strides. Those assigned to three poor ones in a row usually fell way behind.

Value-added models aren't perfect, as even their most ardent supporters concede. Oft-cited shortcomings range from doubts about fairness to broader concerns centered on teaching goals. Those who champion value-added measures also caution against using them as the sole means of evaluating teachers. Kate Walsh, the president of the National Council on Teacher Quality, a research and advocacy group in Washington, has called value-added the best teacher-evaluation method so far. However, she also says it would be a "huge mistake" to rely on it alone or even primarily.

Randi Weingarten, the president of the American Federation of Teachers, doesn't oppose using value-added data but wants to ensure that evaluations are based on "classroom observations, self-evaluations, portfolios, appraisal of lesson plans, students' written work," as well.

"It's a valuable part of the conversation," said Timothy Daly, the president of The New Teacher Project. "It puts what matters most — student achievement — front and center as the most important responsibility for a teacher."

(Freelance writer Barbara Stewart contributed to this article, which was produced by The Hechinger Report, a nonprofit, nonpartisan education-news outlet affiliated with the Hechinger Institute on Education and the Media, based at Teachers College, Columbia University.)

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