The US News Best Global Universities Subject Rankings 2021 analyses 38 subjects grouped into four broad fields: Arts & Humanities, Computer Science & Engineering, Hard Sciences and Soft Sciences. The rankings are powered by Clarivate Analytics InCites (data for the five-year period 2014 - 2018). Depending on the subject, the number of universities ranked ranged from a low of 159 in Mechanical engineering to a high of 1,188 in Chemistry. In total, 12,746 universities were ranked in all 38 subjects. US News subject rankings use 13 indicators  - various bibliometric measures, including publications and citations, as well as indicators for global and regional reputation in each specific subject are considered. The weights and factors used to compute the 38 subject rankings are:

Global research reputation (weights: 12.5%-20.0% or N/A)

Regional research reputation (weights: 12.5%-15.0% or N/A)

Publications (weights: 10.0%-17.5%)

Books (weights: 15.0% or N/A)

Conferences (weights: 2.5%-10% or N/A)

Normalized citation impact (weights: 7.5%-12.5%)

Total citations (weights: 7.5%-17.5%)

Number of publications that are among the 10 percent most cited (weights: 7.5%-15.0%)

Percentage of total publications that are among the 10 percent most cited (weights: 5.0%-7.5%)

Number of highly cited papers that are among the top 1 percent most cited in their respective field (weights: 5.0%-7.5% or N/A)

Percentage of total publications that are among the top 1 percent most highly cited papers (weights: 5.0%-7.5% or N/A)

International collaboration – relative to country (weights: 2.5%-7.5%)

Percentage of total publications with international collaboration (weights: 2.5%-7.5%).

Each indicator used in the subject rankings was based on bibliometric and global and regional reputation data compiled for that specific subject. U.S. News tailored the subject ranking methodology to the different publication characteristics of that field. For the 38 subject rankings different numbers of ranking indicators were considered, e.g. a distinct ranking methodology for arts and humanities were developed, taking into account key characteristics of that field, in which publications play a significantly smaller role. For the arts and humanities ranking, the number of publications or other indicators that relate to publications and citations were weighted far less than they were in the other subject areas. This also means that the conferences and books indicators were used and heavily weighted but weren't used in almost all the other subject rankings, and that both global research reputation and regional research reputation were weighted more heavily than in the other subject rankings.

The 10 new subject rankings do not use either global research reputation or regional research reputation as part of their methodology, and therefore their entire methodology is based on academic research performance data for various bibliometric measures, including publications and citations.