Students who change schools often because they lack stable housing are less likely to graduate, have lower attendance rates and are twice as likely to repeat a grade. Researchers say 75 percent of those who become homeless during their teen years drop out. Under federal law, most school districts have programs designed to help homeless students enroll and remain in school. In the 2010-2011 school year, the number of homeless students topped 1 million for the first time ever. A steady rise in that statistic since the 1980s, when the majority of homeless children did not attend school, shows that efforts to identify homeless students and get them into the classroom are beginning to pay off. But advocates for the homeless say more needs to be done to make sure they graduate and that the root causes of homelessness -- poverty and a lack of affordable housing -- have not been adequately addressed.

Marcia Clemmitt is a veteran social-policy reporter who joined CQ Researcher after serving as editor in chief of Medicine and Health, a Washington-based industry newsletter, and staff writer for The Scientist. She has also been a high school math and physics teacher. She holds a bachelor's degree in arts and sciences from St. Johns College, Annapolis, and a masters degree in English from Georgetown University.