Citations, evaluated in some fashion to take into account the size of institution, are the best understood and most widely accepted measure of research strength.
Often calculated on a “per paper” basis, the QS World University Rankings™ has adopted a “per faculty member” approach since its inception in 2004. The Citations per Faculty score contributes 20% to the overall rankings score.
QS World University Rankings
For the calculation of this indicator, QS gathers two distinct datasets:
Citations count for the last five years
There are three major sources of publication and citation data worldwide, these are the Web of Science from Thomson Reuters; Scopus from Elsevier and Google Scholar. In the first three years of the QS World University Rankings™, results from the Essential Science Indicators (ESI), a subset of the Web of Science were used. In 2007, the switch was made to Scopus for a number of reasons, but principally due to broader journal coverage leading to results for a larger number of institutions.
A key development in 2011 was the exclusion of self-citations.
In 2015, two significant additional modifications have been applied:
- Papers featuring authors from more than ten affiliated institutions have been excluded – this represents around 0.34% of the database and prevents highly cited material produced by very large research groups conferring too much credit on institutions who have only contributed in very small part to the work. Whilst often high-profile and important research, these papers often cause a distortion for a university that may not be especially research active otherwise.
- Faculty Area Normalization – due to publishing patterns and practices, a straight ratio of citations per faculty places a strong emphasis on life sciences and medicine. In consultation with advisors and participants, QS has opted to adopt a model which aims to equalize the influence of research in our five key faculty areas. A more detailed technical explanation of how this works can be found here.
Full Time Equivalent (FTE) faculty
Faculty numbers used are totals… whilst it would be ideal to separate the notions of teaching and research and use the former for calculating the Student Faculty Ratio and the latter for this indicator, it has not been possible to do so as data to that degree of distinction has so far proved unavailable for many countries in the study. The definition of exactly what data we request has evolved gradually over the years to minimize ambiguity.
This indicator is calculated using data from Scopus, the world’s largest abstract and citation database of peer-reviewed literature, which contains 47 million records and over 19,500 titles from 5,000 publishers worldwide.
Scopus is a rapidly evolving system and that’s why data included in the QS export may differ significantly from the current content of Scopus online.
Many commentators have suggested that, given the accepted validity of citations, this measure should carry a significantly higher weighting than it does. Ultimately, however, this places extremely strong emphasis both on medical and life sciences and on institutions from countries where the principal medium of instruction is English.
Whilst it has its critics, the Academic Reputation Survey places equal emphasis on Arts and Social Sciences as it does on Natural and Life Sciences. This is its great strength and, above all, the reason why it carries such a high weighting.
At time of writing, Scopus is working to add more books to its index, which ought to help in less scientific fields ad QS continue to seek alternative measures to evaluate outputs from lower citing disciplines.