Methodology: Best Science Schools Rankings

Rankings of doctoral programs in the sciences are based solely on the results of surveys sent to academics in biological sciences, chemistry, computer science, earth sciences, mathematics, physics, and statistics during fall 2009.

The individuals rated the quality of the program at each institution on a scale of 1 (marginal) to 5 (outstanding). 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 in the ranking table. All doctoral surveys were conducted by Synovate.

The universe of schools surveyed in biological sciences, chemistry, computer science, earth sciences, mathematics, and physics consisted of schools that awarded at least five doctoral degrees for the years from 2003 through 2008, according to the National Science Foundation report "Science and Engineering Doctorate Awards."

The American Statistical Association provided U.S. News with eligible programs for statistics. In biological sciences, graduate programs may be offered in a university's medical school or its college of arts and sciences. In statistics, graduate programs may be offered through a biostatistics or statistics department.

Questionnaires were sent to the department heads and directors of graduate studies at each program in each discipline.

Response rates for the doctoral Ph.D. sciences were as follows: for biological sciences, 15%; chemistry, 25%; computer science, 46%; earth sciences, 29%; mathematics, 34%; physics, 31%; and statistics, 67%.

The number of schools surveyed were: biological sciences—256, chemistry—197, computer science—155, earth sciences—112, mathematics—164, physics—169, and statistics—75.

In the Ph.D. sciences rankings, programs with an average peer assessment score of equal to or greater than 2.0 are numerically ranked. All those with average peer assessment scores of less than 2.0 are listed in alphabetical order as RNP, or Rank Not Published by U.S. News.

Specialty rankings in the Ph.D. sciences are based solely on nominations by department heads and directors of graduate studies at peer schools. These respondents ranked up to 10 programs in each area. Those with the most votes appear in the rankings tables.

Rank Not Published means that U.S. News did calculate a numerical ranking for that school/program, but decided for editorial reasons that since the school/program ranked below the U.S. News cutoff that U.S. News would not publish the ranking for that school/program.

U.S. News will supply schools/programs listed as Rank Not Published with their numerical rankings, if they submit a request following the procedures listed in the Information for School Officials.

Schools/programs marked as Rank Not Published are listed alphabetically. Schools offering Ph.D. science programs, whose ranking is based solely on a 5.0 peer assessment score, are numerically ranked down to a peer assessment score of greater than or equal to 2.0. Schools with scores beneath 2.0 are listed in alphabetical order as Rank Not Published.

Schools in the specialty rankings, which are based solely on nominations from school officials, are numerically ranked in descending order based on the number of nominations they received as long as the school/program received seven or more nominations in that specialty area. This means that schools ranked at the bottom of each specialty ranking have received seven nominations.

Unranked means that U.S. News did not calculate a numerical ranking for that school or program. The school or program did not supply U.S. News with enough key statistical data to be numerically ranked by U.S. News. Schools or programs marked as Unranked are listed alphabetically and are listed below those marked as Rank Not Published.