NEW YORK (AP) -- For decades, getting more students into college has been the top priority of America's higher education leaders. But what's the point, a growing number of experts are wondering, when so few who go to school finish a degree?Just 54 percent of students entering four-year colleges in 1997 had a degree six years later -- and even fewer Hispanics and blacks did, according to some of the latest government figures. After borrowing for school but failing to graduate, many of those students may be worse off than if they had never attended college at all.Now the question of what to do about the country's unimpressive and stagnate graduation rates is on the agenda, from college presidents' offices to state houses. The latest sign of the trend comes Wednesday, when former Princeton President William Bowen lays out an ambitious research agenda on the question during a speech in New York.Normally, a scholar's decision to take on an academic topic is hardly news. But Bowen, president of the Andrew W. Mellon Foundation, is the kind of researcher whose work is so influential that his very curiosity about a subject can raise its profile.His data-driven studies on college athletes, affirmative action and college access for the poor have all sparked nationwide debate in recent years, and he attracted widespread attention last year with a speech at the University of Virginia that called for class-based affirmative action in college admissions.Bowen's latest project will examine in detail who graduates and who doesn't -- and why -- at a group of about 20 varied universities. In an interview, he described the message he will deliver to a Goldman Sachs Foundation gathering on issues facing college trustees as his opening salvo on the topic."The United States has always said it believes in opportunity and social mobility and fairness," Bowen said. "If you find that the odds of getting through are very different for different groups of people, that's something you ought to be concerned about."It's known that elite schools have generally higher graduation rates than non-elite schools. But what's less clear is why the graduation rates at seemingly similar colleges vary so much. For instance, the main campuses of Penn State and the University of Minnesota have comparable price tags, student SAT scores, and percentage of students from poor backgrounds. Yet Penn State graduates more than 80 percent of its students, and Minnesota barely half.Racial gaps are another concern. Overall, the federal figures report 57 percent of white students finish their degree, compared with 44 percent of Hispanics and 39 percent of blacks. A 2004 Education Trust report found a quarter of schools have gaps between whites and blacks of 20 points or more.Traditionally, experts say, blame has fallen on high schools, or on the students themselves. William Bowen's studies on college athletes, affirmative action and college access for the poor have sparked debate in recent years."You walk into a high school and 50 percent of the kids aren't graduating, people say 'What's the matter with this place? Get me the principal. Get me the school board. Let's put this place in receivership,"' said Patrick Callan, president of the National Center for Public Policy and Higher Education. "But people walk into (a college) and say 'What's the matter with these students? We gave them a chance to go to college."'While student responsibility is a factor, "an awful lot of institutions just assumed that getting them in the door was the most important thing," said Kati Haycock, director of The Education Trust.Now, both Haycock and Callan say there are signs that is changing. Graduation rates are on the agenda of Education Secretary Margaret Spellings' new national commission on higher education. There is growing research on how colleges can get students more involved in campus life, which makes them more likely to stay enrolled. And Callan says some state legislatures, even in the face of pressure to increase capacity, are exploring budget incentives for schools to improve graduation rates, not just increase enrollment."But you have to do it carefully, because if you put all the incentives on completion then you just encourage colleges to cherry pick the population" of students most likely to graduate, Callan said. "There's already too much of that."Sarah Turner, a University of Virginia education economist, has assembled data showing graduation rates have stagnated over recent decades even as enrollment has climbed. Explanations range from rising college costs to insufficient academic support to students simply not realizing how valuable a college degree is.But which factors matter most, and how they overlap, is not well understood, largely because the topic is hard to measure. Tracking enrollment numbers is relatively easy, but tracking what happens to individual students over six years is much harder.Bowen, however, specializes in studies that look at large numbers of individual students over time. His previous work tapped into a huge data set of student records from a group of about 20 highly selective colleges. Those schools have atypically high graduation rates, but Bowen says his new work will be based on data from a more representative group of less selective schools.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.