The Metropolitan Transportation Authority and the New York Jets have hired appraisers to decide how much the National Football League team should pay for air rights to build a stadium over Manhattan’s West Side rail yards.

The Jets hired Cushman & Wakefield Inc., the world’s largest closely held real estate services provider, to conduct their appraisal. The authority, the nation’s largest transportation agency by ridership, has hired Jerome Haims Realty Inc., a New York City firm that has appraised Rockefeller Center, Yankee Stadium, and the World Financial Center.

The appraisal will be based on the “highest and best use of the property,” said the president of Jerome Haims Realty Inc., Jerome Haims, declining to comment on the scope of his work. “Property is valued based on what you can do with it.”

The authority is counting on payment from the development rights on the 26-acre Hudson Yards to help fill a $15.5 billion gap in the authority’s proposed $27.8 billion 2005-09 capital plan. The rail yards are between 10th and 12th avenues from West 30th Street to West 33rd Street.

The $1.4 billion stadium, part of New York’s bid for the 2012 Olympics, would be built on a platform over the western portion of the yards. The stadium is part of a proposed new commercial and residential district in a 30-block area between 31st Street and 42nd Street along the Hudson River.

Critics of the stadium, like the Regional Plan Association, a nonpartisan policy group, say the appraisal may not value the rail yards based on the planned redevelopment. Mr. Haimes declined to say how the appraisal would be conducted. The appraiser for Cushman & Wakefield, John Busi, did not return a telephone message seeking comment.

Opponents of the stadium plan suffered a setback yesterday, when a state judge rejected their request for an order halting the city’s approval process. The Hell’s Kitchen Neighborhood Association and other opponents argue that the draft environmental impact statement is inadequate because it failed to identify how the city would deal with traffic congestion, subway crowding, and other problems.

State Supreme Court Justice Herman Cahn in Manhattan ruled the court could not interfere with the city’s review until there was a final determination on whether to go ahead with the project.

Assessing the value of the western portion of the rail yards under the current low-density zoning would yield a “a false rating,” reducing the value of the rights, said a spokesman for the Regional Plan Association, Jeremy Soffin.

Authority Chairman Peter Kalikow has said the agency would get “market value” for the air rights over the Hudson Rail Yards, according to MTA spokesman Tom Kelly. It was reported in May that Kalikow estimates the development rights for the Hudson Yards at $1.2 billion.

The Jets plan to pay $800 million for the stadium, not including an annual payment to the authority for the air rights. Mr. Kelly and Jets spokesman Matthew Higgins declined to comment on the appraisals, saying they had not been completed.

Cushman & Wakefield was previously hired by New York City to study demand for commercial and residential development for the West Side development. The firm said the area could support 28 million square feet of office space and 14.6 million square feet of new housing.

The authority, which moves 2.4 billion people a year, is $11.3 billion short of the $17.3 billion needed for core requirements such as maintenance, upkeep, and normal replacement of equipment. The authority has said it also lacks $4.2 billion of the $9.9 billion required for expansion programs such as the Second Avenue subway.