To pick out the most challenging of the nation’s top colleges, we considered schools that admit students with an average Critical Reading/Math SAT score of at least 1250. We then took into account student opinion, quality and quantity of professors (which directly impacts challenge and workload), and drop-out rate. To that end, the total score for each school consisted of several components: College Prowler's "Most Manageable Workload" score (40%), student-to-faculty ratio (25%; from the National Center for Education Statistics), and an analysis of student-posted evaluations on owler's "Most Manageable Workload" score (40%), student-to-faculty ratio (25%; from the National Center for Education Statistics), and an analysis of student-posted evaluations on RateMyProfessors.com (25%; generated by the Center for College Affordability and Productivity, an education think tank). Additionally, we plotted each school's average SAT score for admitted students against its freshman retention rate (percent of first-years who return the following fall; from NCES) to estimate the degree to which each college's actual retention rate differed from what the correlation would predict. We took the results as a measure of relative ease or difficulty, and factored this in as 10% of the overall score.