A 2010 study by the same researchers found similar results for online learning in the Virginia community college system.
Many students need the flexibility of online classes, said Jaggars, co-author of the study. But online learning puts a greater burden on students to manage their time well, she said.
Despite the challenges, nearly all community colleges are expanding online courses while trying to improve course design.
Community colleges are the "unsung heroes" of the nation's education system, President Obama said in 2010 as he opened a White House community colleges summit chaired by Jill Biden, the vice president's wife and a longtime community college instructor. However, months earlier, he'd sacrificed $12 billion to improve community colleges graduation rates in order to pass his health care bill.
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In a 2011 survey, state community college directors said their colleges don't have the funding to reach the president's 2020 goal: Obama wants the United States to lead the world in college graduates.
Joanne Jacobs writes Community College Spotlight for The Hechinger Report, an independent nonprofit education news site. Jacobs also blogs about K-12 education and is the author of Our School: The Inspiring Story of Two Teachers, One Big Idea and the Charter School That Beat the Odds.