The United Federation of Teachers on Tuesday lost what appeared to be its final chance to block the release of thousands of New York City teachers’ ratings, and school officials said they would make the reports public within a couple of weeks.

The union had sued to keep the ratings of 12,700 teachers private, but on Tuesday the New York State Court of Appeals denied its appeal of aNovember ruling by the Appellate Division of State Supreme Court in..., which threw out the union’s lawsuit.

The ratings, known as Teacher Data Reports, are based entirely on student test scores, and were issued over the last three years. In September, city officials announced that they would no longer produce the reports, which will instead be created by the State Education Department for teachers across New York State.

At least a dozen news media organizations have requested access to the city ratings, including The New York Times, and in 2010, the city agreed to release them. But the ratings remained secret while the union’s suit made its way through the courts.

In the suit, the union’s lawyers argued that disclosing the ratings would violate the teachers’ privacy rights. They also said the reports were exempt from disclosure rules because they were subjective and often inaccurate.

Chancellor Dennis M. Walcott has expressed ambivalence about releasing the ratings. In an interview in September, Mr. Walcottworried about the effect it might have on teacher morale.

“I don’t want our teachers stereotyped,” he said. “I don’t have a problem with names being out there, because we should be transparent. But on the other hand I have a responsibility to make sure that we protect our work force as well, and not to have newspaper stories denigrate my work force, because they’re working their butts off to do their job.”

The previous schools chancellor, Joel I. Klein, championed the rankings, and the city has continued to support their release.