WASHINGTON (AP) -- Fewer than half of all students who entered college in 2007 finished school where they started, and almost a third are no longer taking classes toward a degree anywhere, according to review released Monday.

The dire numbers underscore the challenges that colleges confront as they look to bring in more students and send them out into the world as graduates. The numbers also could complicate matters for students at schools with low graduation rates; the U.S. Department of Education's still-emerging college rating system is considering linking colleges' performances with federal financial aid.

Overall, 56 percent of those who started college in 2007 have finished their coursework on any campus, according to the research arm of the National Student Clearinghouse, a nonprofit organization that works with colleges to verify students' enrollment and graduation status.

About 29 percent of those who started college that year are no longer taking classes toward a degree. The researchers also found 43 percent of all students finished their degrees where they started. The number ranges from 67 percent of students who enrolled full time in 2007 to just 19 percent of those who enrolled part time.

Thirteen percent of students who entered college in 2007 finished their degrees at a different school from where they started.

The National Student Clearinghouse Research Center worked with more than 3,500 schools to review almost 2.4 million records and track students as they transfer among schools.

"Conventional approaches fail to capture the complexity of student behavior because they look only at the starting institution where the student first enrolled," said Doug Shapiro, the chief at the National Student Clearinghouse Research Center.

The new analysis indicates students who enter private four-year, not-for-profit schools are more likely to finish their degrees than those who pick public four-year or four-year, for-profit schools.

The research also indicates students who were 20 years old or younger when they started their degree in 2007 were more likely to finish their degree than were older classmates. Of those who were 25 or older when they began their studies, 44 percent did not earn a degree and are no longer enrolled in a program. Those older students, however, were a minority of all new students in 2007 by a 5-to-1 margin.

Among all students who started classwork in 2007, female students enjoyed a 7 percentage point advantage over men when it came to whether they had earned a degree in six years.

The numbers stand to complicate life for students and administrators at schools where many leave campus without a degree in hand. Education Secretary Arne Duncan has proposed linking tuition costs, graduation rates and other data to how much federal money each school receives.

The Education Department is also developing a college rating system set to be published by 2015.

That plan faces fierce opposition from college presidents because no two schools are alike and specific circumstances can create unfair appearances for schools.

Congress, too, has been slow to embrace the plan because no elected official wants to have a home-district or -state college labeled a bad deal.

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  • Washington D.C.

    82,098 graduates, 68.8% of the population. *Washington, D.C. is not a state, but its figures are included in the data. <strong><em>Clarification: Language has been added to indicate that Washington, D.C., while not a state, was included in the census data.</strong></em>

  • Massachusetts

    454,219 graduates, 54.3% of the population

  • North Dakota

    43,893 graduates, 50.8% of the population

  • Minnesota

    350,909 graduates, 49.8% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:UMN-NorthrupMall.jpg" target="_hplink">BenFranske</a>

  • New York

    1,302,196 graduates, 49.6% of the population

  • New Jersey

    520,299 graduates, 47.2% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:Bishop_House-Rutgers_University.jpg" target="_hplink">Lacwal12</a>

  • New Hampshire

    65,715 graduates, 46.0% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:Manch-DownTown.jpg" target="_hplink">Mikespenard</a>

  • Connecticut

    190,044 graduates, 45.9% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:Nhskyline_eastshore.jpg" target="_hplink">Versageek</a>

  • Iowa

    172,115 graduates, 45.5% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:Cleary_Walkway_with_the_Old_Capitol_in_the_background,_University_of_Iowa.JPG" target="_hplink">Magnus Manske</a>

  • Maryland

    339,891 graduates, 45.5% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:UMD_stairway.JPG" target="_hplink">Bgervais</a>

  • Illinois

    798,362 graduates, 45.3% of the population

  • Virginia

    477,103 graduates, 44.6% of the population

  • Vermont

    30,737 graduates, 44.5% of the population Photo Credit: <a href="http://en.wikipedia.org/wiki/File:UVM_Old_Mill_building_20040101.jpg" target="_hplink">Redjar</a>

  • Nebraska

    107,058 graduates, 44.2% of the population

  • Pennsylvania

    654,558 graduates, 43.9% of the population