Rankings of doctoral programs in the sciences are based on the results of surveys sent to academics in computer science, mathematics, and physics during the fall of 2007, in biological sciences and chemistry during fall 2006, and in other fields during fall 2005. The individuals rated the quality of the program at each institution from "marginal" (1) to "outstanding" (5). Individuals who were unfamiliar with a particular school's programs were asked to select "don't know." The schools with the highest average scores among those who rated them were sorted in descending order and appear here. Surveys in biological sciences, chemistry, computer science, Earth sciences, mathematics, and physics were conducted by Synovate.
The universe of schools surveyed in computer science, mathematics, and physics consisted of schools that awarded at least five doctoral degrees, according to the National Science Foundation report "Science and Engineering Doctorate Awards," for the years from 2001 through 2006; in biological sciences and chemistry for the years from 2000 through 2005; and for Earth sciences from 1999 through 2004. In biological sciences, graduate programs may be offered in a university's medical school or its college of arts and sciences. If so, the programs were ranked separately.
Questionnaires were sent to the department heads and directors of graduate studies at each program in each discipline. Response rates were: for biological sciences, 21 percent of those surveyed responded; for chemistry, 32 percent; for computer science, 48 percent; for Earth sciences, 40 percent; for mathematics, 33 percent; and for physics, 32 percent.
Specialty rankings are based solely on nominations by department heads and directors of graduate studies at peer schools from the list of schools surveyed.