As the mayoral election approaches, we all can expect to see more talk from the United Federation of Teachers about why the city’s public school teachers deserve higher salaries. Some of this is directed at Mayor Bloomberg, who could sign a contract with the teachers in advance of the election and thus neutralize a formidable opposing political force. If Mr. Bloomberg declines to cave in, the union rhetoric will be directed at the voters in hopes of electing a Democratic mayor who would presumably be more pliable. And some of the union’s message is directed at Albany, which faces the prospect of complying with the ruling of a state judge, Leland DeGrasse, who has ordered an increase of $23 billion in taxpayer funding for the city’s government-run schools.

The union is only doing what it is supposed to. Fortunately for the taxpayers, though, the union’s voice isn’t the only one in this debate. The National Bureau of Economic Research is now famous as the site of Harvard President Lawrence Summers’s musings on gender differences, but it does some other important work, too. Yesterday, the bureau released a paper titled “The Market for Teacher Quality.” Written by Eric Hanushek of Stanford University’s Hoover Institution, Steven Rivkin of Amherst College, and Daniel O’Brien and John Kain of the University of Texas at Dallas, the paper uses detailed economic and statistical analysis of an urban Texas school district to cast strong doubt on the idea that the good teachers are fleeing the city for the suburbs.

“A commonly voiced policy concern is that large urban districts lose their better teachers to other occupations or to suburban schools. We find little if any support for the notion that the better teachers are the most likely to exit the public schools entirely. To the contrary, teachers exiting Texas public schools are significantly less effective on average in the year prior to leaving than those who remain, and those changing districts are quite similar in terms of effectiveness,” is the way the authors describe their conclusions.” Similarly, there is little systematic evidence in support of the view that the urban district loses its better teachers to the suburbs.

“Much has been made of the fact that salary differentials in metropolitan areas exist and that these may frequently lead to a drain of high quality teachers from urban centers. This view is reinforced by analyses that show urban areas to be net suppliers of teachers to other districts and that show urban districts to lose teachers disproportionately from schools with low achievement and high minority populations. Although high turnover hurts students because of the lower performance of inexperienced (replacement) teachers, the evidence does not support the related concern that the best teachers are those most likely to leave,” the paper says.

Back in May, the president of the UFT, Randi Weingarten, gave a speech in which she claimed, “we are facing a huge brain drain, as teachers continue to leave in record numbers.” Her proposed solution was to spend $750 million taxpayer dollars on “reducing the teacher salary gap between New York City and its surrounding suburbs, a gap that is $10,000 to $15,000 wide.” She said, “That way, even our best schools can retain their excellent teachers.” The next time she raises the issue, whether in public or at the negotiating table, Mayor Bloomberg may just want to pull out a copy of the NBER paper on “The Market for Teacher Quality” and try teaching its conclusions to the teachers.