We began with the 3,487 postsecondary institutions in the fifty states and Washington, D.C., that were listed in the Integrated Postsecondary Education Data System (IPEDS) as being active in the 2016-17 academic year and had a Carnegie basic classification in 2015 of between 1 and 23, excluding many colleges that only grant certificates as well as special-focus institutions such as medical schools or rabbinical programs. We dropped any colleges that were graduate-only institutions, did not participate in any federal financial aid programs, were one of the five service academies (to be consistent with the main rankings), and that we know have closed or merged since 2016-17. An additional 138 colleges were excluded for having fewer than 100 students in any of the last three years in which they were open.
The next sample restriction was to exclude colleges that did not have data on all of the outcome measures. Another 311 colleges were dropped for not participating in the College Board's Annual Survey of Colleges, which is key in our rankings. Forty-one colleges did not have data on the percent of adult students, 277 colleges did not have data on average earnings of independent students, and we excluded thirty-two colleges that participated in the federal student loan program but did not report a separate repayment rate for independent students. As we used the percentage of adult students as one of our metrics, colleges with insufficient numbers of independent students to have a separate repayment rate for independent students were unlikely to score highly in this ranking anyway. For three colleges that served at least 75 percent adult students and did not have separate data on earnings or repayment rates for independent students, we instead used data for all students. Our resulting sample is 2,212 colleges, of which 1,124 are considered four-year colleges (based on Carnegie classification and whether they awarded more bachelor's degrees than certificates or associate's degrees), and 1,088 are two-year colleges.
As a final precaution to highlight especially questionable colleges, we used the Department of Education's list of colleges on the most serious level of heightened cash monitoring for significant financial or operating concerns.
We used the seven metrics in this year's rankings as we did in 2016 and 2017--and we added one, thanks to new data from the federal government. The metrics are the following:
(1) Ease of transfer/enrollment...