The QS World University Rankings® have been in existence since 2004, but since 2011 the study has been extended to encompass a range of popular individual subjects.The majority of prospective international students begin their search knowing what they want to study before considering where, so understanding the comparative quality of institution by subject is fundamental to the QS mission to support students in their decision making. QS aims to add more depth, more detail and more subjects to this work year by year and anticipates that these tables will, in time, become more important than the overall result.Any international ranking faces various challenges relating to the equal availability and applicability of data within different countries and university systems. Many indicators of university quality commonly used in domestic rankings, such as the average entry tariff of admitted students, are not yet applicable on an international level and are thus not included in any of these exercises. And in areas where universities themselves can provide data, the efficiency with which it is collected varies by region. While the depth of data available from the UK, Australia and the US may be exemplary it is yet to be matched by that in India, Greece or Brazil, for example. These challenges become more pronounced when the focus of a ranking is narrowed to a particular aspect of university performance. While it may be reasonable to expect a university to have a decent understanding of its average faculty-student ratio, to break that down by faculty or department is difficult in even the most advanced cultures of data provision. For this reason the methodology for QS World University Rankings by Subject has been narrowed to include only those indicators that bypass the direct involvement of institutions and can reliably be stratified by subject discipline. This page outlines the QS approach for doing so, and how it has been used to produce the new QS World University Rankings® by Subject.
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