The organization identified 222 metropolitan statistical areas with at least 15,000 students, based on U.S. Census Bureau standards, and then chose the top 75. It then ranked cities in four population categories, from the largest metro areas to small college towns. The rankings are based on 12 criteria in three general categories: academic environment (with an eye toward factors such as student diversity and degree attainment), quality of life (arts and leisure, cost of living, etc.) and professional opportunity (such measures as earning potential, unemployment rate, entrepreneurial activity).