As many as one in three first-year students doesn't make it back for sophomore year. The reasons run the gamut, of course, from family problems to loneliness to academic struggles to a lack of money. If schools you're considering have a low freshman retention rate, you'll want to ask the admissions office why. The retention rates shown below, from highest to lowest, are the average proportion of freshmen entering starting in fall 2006 through fall 2009 who returned to school the following fall.