The Washington Monthly ranking of America’s best community colleges is based on two sources of information: the Community College Survey of Student Engagement (CCSSE) and U.S. Department of Education measures of student retention and completion.

The CCSSE survey is managed by a nonprofit organization of the same name housed at the University of Texas at Austin. The survey instrument is given to a representative sample of students at community colleges that choose to administer the survey. Since 2003, the CCSSE has been administered at the large majority of American community colleges. All CCSSE results are published on the organization’s Web site.

Because most community colleges do not administer the survey every year, we combined results from the three most recent available years: 2010, 2011, and 2012. For colleges that participated more than once, we used the most recent year. More than two-thirds of all community colleges—roughly 700 institutions—were included in our analysis. We publish results for the top fifty institutions.

The CCSSE survey is comprised of more than 100 questions on a range of topics including teaching practices, student workload, interaction with faculty, and student support. The CCSSE combines the results of those questions into aggregate “benchmark” scores in five categories: “Active and Collaborative Learning,” “Student Effort,” “Academic Challenge,” “Student-Faculty Interaction,” and “Support for Learners.” The benchmark scores are standardized to range from 0 to 100 with an average score of 50.

The CCSSE benchmarks comprise five-eighths of each college’s ranking. As with any sample-based survey, CCSSE results have statistical margins of error. Readers should be mindful of this when interpreting the rankings, particularly when differences between colleges are small.

The remaining three-eighths of each college’s ranking is based on data compiled annually by the National Center for Education Statistics at the U.S. Department of Education. The first measure is the first-year retention rate, defined as the percentage of first-time fall enrollees who are still enrolled the following fall, or earn a degree or certificate during that time. The second measure is the percentage of first-time, full-time, degree-seeking students who graduate or transfer within three years of enrolling. The third measure is the ratio of all degrees awarded during a given academic year to the number of full-time equivalent students enrolled, with two-year degrees given twice the weight of one-year degrees. This measure has the advantage of including students who enroll part-time or transfer in from other colleges, and as such are not included in the graduation and retention rate statistics.

All three measures are calculated as the average of results from the three most recent years. The data sources and methods used to calculate the three U.S. Department of Education statistics are identical to those used by the Aspen Prize for Community College Excellence.