January 5, 2009 Our rankings measure academic quality and affordability, with quality accounting for two-thirds of the total. We started with data on more than 600 private institutions provided by Peterson's, then added our own reporting. Our list ranks the top 50 universities and liberal arts colleges in separate tables. To determine each category, we used the Carnegie classification system, which organizes institutions based on the highest level and number of degrees offered. Admission rate is the percentage of applicants offered admission. SAT or ACT shows the percentage of the 2007-08 freshman class that scored 600 or higher on the verbal and math SATs, or 24 or higher on the ACT. Student/faculty ratio is the average number of students per instructor. Graduation rate is the percentage of freshmen who earned a bachelor's degree within four years or five years. Total cost for academic year 2008-09 includes tuition, mandatory fees, room and board, and estimated expenses for books. Cost after need-based aid is the 2008-09 total cost minus the average need-based aid amount (excluding loans). Aid from grants is the percentage of the average aid package that came from grants. Cost after non-need-based aid is the 2008-09 cost for a student with no demonstrated need after subtracting the average non-need-based aid amount (excluding loans). Non-need-based aid is the percentage of all undergraduates without need who received non-need-based aid. Average debt at graduation is the average amount owed by graduates who took out education loans. Sponsored Content To break ties, we used academic-quality scores and average debt at graduation.