There are multiple world university rankings available – with the best-known being the QS World University Rankings®, Times Higher Education World University Rankings, and the Academic Ranking of World Universities (ARWU) – and each one uses a different methodology. This can sometimes be confusing, as it’s not always easy to see why a university is ranked differently, or why the order within a country changes depending on which table you view.\r\nTo clarify how these different outcomes are reached, below is an overview of the methodologies used for these three major world university rankings…\r\nQS World University Rankings®\r\nThe QS World University Rankings assesses universities on six performance indicators, relating to research, teaching, employability and internationalization. To be eligible for inclusion, institutions must teach at both undergraduate and postgraduate level, and conduct work in at least two of five broad faculty areas (arts and humanities; engineering and technology; social sciences and management; natural sciences; life sciences and medicine).\r\n\r\nAcademic reputation (worth 40% of the overall score) Based on a global survey of academics, who are asked to identify the leading institutions in their field.\r\nEmployer reputation (10%) Based on a global survey of graduate employers, who are asked to identify the institutions producing the best graduates in their sector.\r\nStudent-to-faculty ratio (20%) An indication of commitment to high-quality teaching and support.\r\nResearch citations per faculty member (20%) This is normalized by subject area, and reflects the impact of an institution’s research.\r\nProportion of international faculty (5%) A measure of an institution’s success in attracting faculty from overseas.\r\nProportion of international students (5%) A measure of an institution’s success in attracting students from overseas.\r\n\r\nThe interactive results table can be filtered to show the scores for each of these six indicators, showing where each institution’s comparative strengths and weaknesses lie. You can find out more about the QS World University Rankings methodology here.\r\nTimes Higher Education World University Rankings\r\nThe Times Higher Education World University Rankings uses 13 performance indicators, grouped into five categories. Institutions are excluded if they do not teach at undergraduate level, or if their research output is below a certain threshold.\r\n\r\nTeaching (worth 30% of the overall score) Based on a reputation survey (15%), staff-to-student ratio (4.5%), doctorate-to-bachelor’s ratio (2.25%), doctorates-awarded-to-academic-staff ratio (6%) and institutional income (2.25%).\r\nResearch (30%) Based on a reputation survey (18%), research income (6%) and research papers published per faculty member (6%).\r\nResearch citations (30%) Based on the number of citations a university’s research obtains, normalized by subject area.\r\nInternational outlook (7.5%) Based on international-to-domestic-student ratio (2.5%), international-to-domestic-staff ratio (2.5%) and international research collaborations (2.5%).\r\nIndustry income (2.5%) Based on income earned from industry, relative to the number of academic staff employed, and adjusted for PPP.\r\n\r\nThe published results can be sorted to show universities’ scores for each of the five categories, but not for the individual indicators within each category.\r\nAcademic Ranking of World Universities (ARWU)\r\nAlso widely known as the Shanghai Ranking, the Academic Ranking of World Universities (ARWU) assesses six performance indicators, all relating to research excellence. The ranking considers all institutions with Nobel Laureates, Fields Medalists, highly cited researchers, papers published in Nature or Science, or a significant number of papers indexed by the Science Citation Index-Expanded (SCIE) or Social Science Citation Index (SSCI).\r\n\r\nAlumni (worth 10% of the overall score) Based on the number of alumni of an institution who have won Nobel Prizes and Fields Medals, with greater weight given to more recent recipients.\r\nAwards (20%) Based on the number of staff affiliated with an institution who have won Nobel Prizes in physics, chemistry, medicine and economics, and Fields Medals in mathematics, with greater weight given to more recent recipients.\r\nHighly cited researchers (20%) Based on an institution’s number of highly cited researchers, according to the latest list published by Thomson Reuters.\r\nPapers in Nature and Science (20%) Based on the number of papers published in these two influential journals, drawing on a four-year period. For institutions specialized in social sciences and humanities, this category does not apply.\r\nPapers indexed (20%) Based on the number of papers indexed in the Science Citation Index-Expanded and Social Science Citation Index\u0026nbsp;in the preceding calendar year, with a double weighting for papers indexed in the Social Science Citation Index.\r\nPer capita performance (10%) The weighted scores of the other indicators, divided by the number of full-time equivalent academic staff.\r\n\r\nThe published ARWU results can be sorted to show performance in each of these six indicators.\r\nGot more questions about any of these world university rankings? Take a look at our frequently asked questions, or ask your own in the comments below.\r\nThis article was updated in June 2017.