HERI's annual "The American Freshman: National Norms" report found that less college students than ever are enrolled at their first choice schools. The reason for this appears to be fairly clear - high costs.
While more than three-quarters (75.5%) of students were admitted to their dream colleges, only 56.9% of those accepted ended up enrolling. According to HERI, this is due to a combination of potentially high costs at the student's top choice, and attractive financial aid offers elsewhere.
As they report:
Although inadequate and higher costs prompted many students to turn down admissions offers by their first-choice institutions in lieu of admissions offers elsewhere, other students who were accepted to their first-choice college enrolled elsewhere due to more attractive financial aid packages and lower college costs at competing campuses.
Via HERI, this graph shows what prompted students to turn down admissions offers from their dream colleges:
See the full American Freshman report at the Higher Education Research Institute >>