In the debate over affirmative action in undergraduate admissions, some have suggested that colleges need broader definitions of diversity -- and that they should consider socioeconomic class as well as such factors as race and ethnicity. Many colleges do so, and explicitly note that they are trying to recruit "first generation" students or those from low-income families.

What about graduate admissions? Individual departments tend to make the decisions -- and those decisions affect not only who is studying for a Ph.D. but who will be in the next generation of professors.

A study just published in PS: Political Science and Politics suggests that in graduate departments, class may be nowhere to be found in admissions decisions.

Kenneth Oldfield, an emeritus professor of public administration at the University of Illinois at Springfield, surveyed graduate departments of political science on admissions practices. Nearly all had policies stressing their commitments to diversity and a desire for a racially and ethnically diverse student body, and some expressed explicit support for affirmative action. And while applicants were not required to do so, they had the chance to indicate their racial or ethnic status.

But when it came to socioeconomic status, the picture was very different. Oldfield asked departments whether they inquired about two pieces of information -- parental education and parental occupation -- commonly used to measure socioeconomic status. Only 12 percent of programs sought information about the former and 8 percent the latter. Of those that did ask, the information wasn't generally used as a factor in admissions decisions, but as a means of determining whether applicants might be eligible for various fellowships if admitted.

Oldfield notes in the article that the political science association has repeatedly issued various reports and studies calling for the discipline to be fully inclusive and to consider issues of class. But there's not much evidence of anyone paying attention, he finds, at least in grad admissions.

Thomas P. Rock, immediate past president of the National Association of Graduate Admissions Professionals, said that he suspects the results would be similar in other disciplines. Rock, interim executive director of enrollment services at Teachers College of Columbia University, said that most graduate applications follow federal race and ethnicity categories and leave it at that. He said that he has heard some discussion in the graduate admissions world of adding a "white Appalachian" category.

Rock said that there is interest among graduate admissions officials in looking for ways to consider socioeconomic status. But he said that one concern is whether asking questions might leave some applicants nervous that their lack of money would count against them in admissions.

Still, Rock said that the political science study pointed to an important issue. "Personally, I think we have to look at all categories. Many schools -- Teachers College included -- are discussing how to include socioeconomic status," he said.

In an interview, Oldfield stressed that he was not arguing that there is an either/or dilemma with existing measures of diversity and socioeconomic class. "I don't think we should replace one with the other. I think diversity really means diversity and that class should be thrown into the mix," he said.

Oldfield was raised by one of his grandmothers, a woman who never graduated from high school and whose home didn't have books. That background helped shape his experiences, he said, adding that many in higher education -- while studying issues of class -- don't like to think how it affects their own programs.

When people raise issues of why class isn't considered, Oldfield said, "most people, once they start talking, say that they'd never thought about it," but agree that class matters. "One of my motivations here is that I think it's an overlooked issue."