World University Rankings by Subject

An Overview

QS World University Rankings by Subject ranks the world’s top universities in individual subject areas, covering 5 broad subject areas and 48 specific subject areas. The rankings aim to help prospective students identify the world’s leading schools in their chosen field in response to high demand for subject-level comparisons. In 2022, ITS is ranked in 4 specific subject areas: Chemical Engineering, Computer Science, Electrical Engineering, and Mechanical Engineering.

Each of the subject rankings is compiled using five sources. The first two of these are QS’ Global Surveys of Academics and Employers, which are used to assess institutions’ international reputation in each subject. The other three indicators assess research impact, based on research citations per paper, H-Index in the relevant subject, and International Research Network (IRN).

These five components are combined to produce the results for each of the (broad) subject rankings, with weightings adapted for each discipline (below is weighting for: Engineering and Technology):

Academic Reputation

QS’s global survey of academics has been at the heart of the QS World University Rankings since their inception in 2004. In 2020, the QS World University Rankings by Subject draws on responses from nearly 95,000 academics worldwide.

Having provided their name, contact details, job title and the institution where they are based, respondents identify the countries, regions and faculty areas they are most familiar with, and up to two narrower subject disciplines in which they have expertise. For each of the (up to five) faculty areas they identify, respondents are asked to list up to 10 domestic and 30 international institutions which they consider to be excellent for research in the given area. They are not able to select their own institution.

For the QS World University Rankings by Subject, the results of the survey are filtered according to the narrow area of expertise identified by respondents. While academics can select up to two narrow areas of expertise, greater emphasis is placed on respondents who have identified only one. This metric plays a crucial role in determining the overall score, accounting for 40%.

Employer Reputation

QS World University Rankings are unique in incorporating employability as a key factor in the evaluation of international universities. In 2020, the QS World University Rankings by Subject draws on nearly 45,000 survey responses from graduate employers worldwide.

The employer reputation survey works on a similar basis to the academic one, but without channeling for different faculty areas. Employers are asked to identify up to 10 domestic and 30 international institutions they consider excellent for the recruitment of graduates. They are also asked to identify the disciplines from which they prefer to recruit. By examining the intersection of these two questions, we can infer a measure of excellence in a given discipline. The overall score is quite largely determined by this metric, which is worth 30%.

Citations per Paper

For the QS World University Rankings by Subject we measure citations per paper, rather than citations per faculty member. This is due to the impracticality of reliably gathering faculty numbers broken down by discipline for each institution.

A minimum publication threshold is set for each subject to avoid potential anomalies stemming from small numbers of highly cited papers. Both the minimum publications threshold and the weighting applied to the citations indicator are adapted in order to best reflect prevalent publication and citation patterns in a given discipline. All citations data is sourced from the Scopus, spanning a five-year period. This metric accounts for 10% of the total score.

H-Index

Since 2013, a score based on ‘h-index’ has also been incorporated in the QS World University Rankings by Subject. The h-index is a way of measuring both the productivity and impact of the published work of a scientist or scholar. The index is based on the set of the academic’s most cited papers and the number of citations that they have received in other publications.

The h-index can also be applied to the productivity and impact of a group of scientists, such as a department, university or country, as well as a scholarly journal. The index was suggested by Jorge E. Hirsch, a physicist at UCSD, as a tool for determining theoretical physicists’ relative quality, and is sometimes called the Hirsch index or Hirsch number. This metric carries a weight of 10% in the overall score

International Research Network (IRN)

The International Research Network (IRN) was included for the first time in the 2016/17 edition of the QS University Rankings: Latin America, and has now been expanded to all the other regional rankings.

Since 2022, QS has included IRN Index in the ranking of broad subject areas (Arts & Humanities, Engineering & Technology, Life Sciences & Medicine, Natural Sciences, and Social Sciences & Management).

The Margalef Index, widely used in the environmental sciences, has been adapted to estimate the richness of the selected international research partners for a given institution. IRN Index reflects the ability of institutions to diversify the geography of their international research network by establishing sustainable research partnerships with other higher education institutions. It also reflects the efficiency of this as QS looks at the diversity of partner locations against the efforts needed to achieve such a diversity. Specifically, the QS International Research Network index is calculated with the following formula:

IRN Index = (L – 1) / ln P,

where L is the number of locations and P is the number of international partners.

This metric considers the distinct count of international peer institutions collaborating in 3 or more papers indexed by Scopus in a five-year period.

As in other cases when citations and papers are processed in QS’ regional rankings, IRN Index is normalized by QS’ five faculty areas: it is calculated per each of them and then averaged to ensure that the influence of research is equalized across different fields. This metric is worth 10% of the overall number.

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