The Newsweek rankings are based on six factors, including the school's four-year, on-time graduation rate (25-percent weight); percentage of 2011 graduates who were accepted to college (25-percent weight); AP/IB/AICE tests per student (25-percent weight); average AP/IB/AICE exam score (10-percent weight); and percentage of students enrolled in at least one AP/IB/AICE course (5-percent weight).