What are the most popular global University Rankings? What are their ranking coverage, methodology, strengths and weaknesses? These are some interesting questions that our team at uniRank will try to give an answer with the following 2023 short guide and reviews of some of the top world university rankings.Review of global Academic University Rankings
As mentioned in a previous article, Academic University Rankings adopt a ranking methodology that mainly focuses on academic factors and criteria in order to generate their rankings. Some of the most well-known global academic university rankings, listed in order of the first year of publication, include:Academic Ranking of World Universities (ARWU) 
Firstly published in 2003 and also known as the Shanghai Ranking, this is a ranking of universities originally published by Shanghai Jiao Tong University in China. Since 2009, the ARWU ranking has been published by ShanghaiRanking Consultancy, a fully independent private organization specializing in higher education intelligence.
- ARWU ranking frequency -
This ranking is published annually.- ARWU ranking coverage -
In total, approximately 2,500 universities around the world are ranked but only the top 1,000 are actually selected and published in the final ARWU ranking (2022 data).- ARWU ranking methodology -
The Academic Ranking of World Universities uses 6 academic indicators to rank world universities; the ranking criteria and weights include:1) the number of alumni winning Nobel Prizes and Fields Medals (10%)
2) the number of staff winning Nobel Prizes and Fields Medals (20%)
3) the number of highly cited researchers selected by Clarivate (20%)
4) the number of papers published in journals of Nature and Science (20%)
5) the number of papers indexed in Science Citation Index Expanded and Social Sciences Citation Index in the Web of Science (20%)
6) per capita performance of a university (10%)
The Academic Ranking of World Universities is, therefore, a university ranking that prioritizes and somehow favors, in the chosen methodology and its ranking criteria, universities with high research output and that have produced Nobel laureates, highly cited researchers or papers published in top English-language journals.
- ARWU ranking criticism -
a) Methodology concerns: firstly, the ARWU ranking mainly focuses on research output (bias towards research), which means that universities with a strong research focus tend to rank higher. This may not accurately reflect the overall quality of a university, especially if the university places a greater emphasis on teaching or community engagement.Secondly, the ARWU ranking places a strong emphasis on publications in English-language journals (bias towards English language institutions), which may disadvantage universities in non-English speaking countries or those that focus on research in non-English languages.
b) Limited scope: the ARWU ranking only considers universities that have produced Nobel laureates, highly cited researchers or papers published in top journals. This means that smaller or more specialized universities may be overlooked and that the rankings are skewed towards universities in science and technology fields.
c) Limited relevance: the ARWU ranking may be less relevant to students or employers, who may be more interested in factors such as the quality of teaching, job placement rates or student satisfaction.
d) Limited coverage: the ARWU ranking takes into consideration only 2,500 higher education institutions around the world and only 1,000 of them are selected for the final published ranking.
Overall, while the ARWU is a well-respected academic university ranking system, it is important to keep in mind, as with every other university ranking, its limitations and potential biases.
QS World University Rankings 
QS World University Rankings is a ranking of world universities compiled and published by Quacquarelli Symonds (QS), a fully independent and private British education consultancy firm, since 2004. QS also regularly publishes other regional and specialized university rankings.
- QS ranking frequency -
This ranking is published annually.- QS ranking coverage -
The QS World University Rankings include almost 1,500 selected institutions from around the world (2023) that have met their eligibility criteria.- QS ranking methodology -
The QS World University Rankings are based on 6 academic indicators:1) Academic Reputation (40%)
2) Faculty Student Ratio (20%)
3) Citations per Faculty (20%)
4) Employer Reputation (10%)
5) International Faculty Ratio (5%)
6) International Student Ratio (5%)
- QS ranking criticism -
a) Methodology concerns: firstly, the QS World University Rankings have faced criticism for their methodology, particularly with regard to the excessive weight given to certain factors, such as academic reputation (40%) and faculty/student ratios (20%).Secondly, some have argued that the survey-based reputation scores may be subject to bias and are not a reliable indicator of the quality of education, research or teaching at a particular higher education institution; data, obtained through surveys sent to a selected target, is currently used for the academic reputation (40% weight) and employer reputation (10%) components, totaling 50% of the ranking algorithm.
Thirdly, some have also criticized the use of self-reported data by universities which may be subject to manipulation to achieve better rankings if not independently verified.
b) Limited scope: the QS World University Rankings only select universities that meet their eligibility criteria of subject comprehensiveness and level comprehensiveness which excludes, for example, single-faculty institutions. This means that vocational or specialized institutions may be overlooked.
c) Limited relevance: similar to the ARWU ranking, the QS World University Rankings may be less relevant to students or employers, who may be more interested in factors such as the quality of teaching, job placement rates or student satisfaction.
d) Limited coverage: the QS World University Rankings take into consideration only 1,500 higher education institutions around the world. For an extended number of universities the audience can, however, rely on other regional university rankings released by the same publisher; being the ranking methodology of these regional rankings different from the QS World University Rankings some issues may arise when trying to compare the two rankings.
Overall the QS World University Rankings is a well-regarded academic university ranking system but it is important to keep in mind its limitations and potential biases.
Times Higher Education World University Rankings 
The Times Higher Education World University Rankings is a ranking of world universities compiled and published by Times Higher Education (THE), a UK-based media company, since 2004.
- THE Rankings frequency -
This ranking is published annually.- THE Rankings coverage -
The Times Higher Education World University Rankings include 1,800 selected institutions from around the world (2023).- THE Rankings methodology -
The THE rankings use 13 indicators across 5 categories: teaching, research, citations, international outlook and industry income:1) Teaching (the learning environment): 30%
- Reputation survey (15%)
- Staff-to-student ratio (4.5%)
- Doctorate-to-bachelor's ratio (2.25%)
- Doctorates-awarded-to-academic-staff ratio (6%)
- Institutional income (2.25%)
2) Research (volume, income and reputation): 30%
- Reputation survey (18%)
- Research income (6%)
- Research productivity (6%)
3) Citations (research influence): 30%
4) International outlook (staff, students, research): 7.5%
- Proportion of international students (2.5%)
- Proportion of international staff (2.5%)
- International collaboration (2.5%)
5) Industry income (knowledge transfer): 2.5%
The THE Rankings methodology, with its high number of indicators, seems to be one of the most complex and comprehensive ones among the top university rankings available today.
- THE Rankings criticism -
a) Methodology concerns: firstly, the methodology used by Times Higher Education to rank universities has been criticized for relying heavily, similarly to the QS World University Rankings, on reputation surveys. The ranking relies on data from various sources, including academic publications, reputation surveys and research income. However, some have argued that the survey-based reputation scores are not a reliable indicator of the quality of education, research or teaching at a particular higher education institution; data, obtained through surveys sent to a selected target, is currently used for the teaching reputation (15% weight) and research reputation (18%) components, totaling 33% of the ranking algorithm.Secondly, some have also criticized the use of self-reported data by universities which may be subject to manipulation if not independently verified.
Lastly, the THE Rankings, similar to the ARWU Rankings, have been criticized for being biased toward English-language institutions, as the ranking heavily relies on publications in English-language journals. This bias may disadvantage institutions in non-English speaking countries that may produce high-quality research but are less likely to publish in English-language journals.
b) Limited relevance: similar to the ARWU Rankings and the QS World University Rankings, the THE Rankings may fail to capture broader aspects of university performance and, therefore, be less relevant to students or employers, who may be more interested in other aspects such as the quality of teaching, job placement rates or student satisfaction.
c) Limited coverage: the THE Rankings take into consideration only 1,800 higher education institutions around the world.
Overall the Times Higher Education World University Rankings, with their extensive list of methodology criteria and indicators, are recognized as one of the leading academic university rankings in the world; it is still important to keep in mind its limitations and potential biases.
U.S. News & World Report Best Global Universities Rankings 
The U.S. News & World Report Best Global Universities Rankings is a ranking of universities around the world published by U.S. News & World Report, a media company based in the United States, since 2014.
- USNWR-BGU Rankings frequency -
This ranking is published annually.- USNWR-BGU Rankings coverage -
The U.S. News & World Report Best Global Universities Rankings include 2,000 selected institutions from around the world (2023).- USNWR-BGU Rankings methodology -
The rankings are based on 13 indicators:1) Global research reputation 12.5%
2) Regional research reputation 12.5%
3) Publications 10%
4) Books 2.5%
5) Conferences 2.5%
6) Normalized citation impact 10%
7) Total citations 7.5%
8) Number of publications that are among the 10% most cited 12.5%
9) Percentage of total publications that are among the 10% most cited 10%
10) International collaboration - relative to country 5%
11) International collaboration 5%
12) Number of highly cited papers that are among the top 1% most cited in their respective field 5%
13) Percentage of total publications that are among the top 1% most highly cited papers 5%
Similarly to the THE Rankings, the USNWR-BGU Rankings methodology, with its high number of indicators, seems to be one of the most complex and comprehensive ones among the top university rankings available today.
- USNWR-BGU Rankings criticism -
a) Methodology concerns: firstly, the USNWR-BGU Rankings heavily rely on research performance metrics, such as citation counts, which can be biased towards universities that have been around for longer and have larger research budgets. This can disadvantage newer or smaller universities that are producing high-quality research but are not yet well-established.Secondly, the USNWR-BGU Rankings tend to favor universities in English-speaking countries (bias towards English language institutions), which can disadvantage universities in non-English-speaking countries, even if they are producing high-quality research.
b) Limited scope: the USNWR-BGU Rankings is focused primarily on STEM (science, technology, engineering and mathematics) fields and neglects other important disciplines such as humanities, social sciences and arts. This can lead to an incomplete picture of a university's overall quality.
c) Data accuracy: the USNWR-BGU Rankings uses data from third-party sources such as Scopus, which has been criticized for incomplete coverage of non-English language publications, leading to an incomplete and potentially biased view of research output.
d) Limited coverage: the USNWR-BGU Rankings take into consideration only 2,000 higher education institutions around the world.
Overall, while the U.S. News & World Report Best Global Universities Rankings is a well-respected university ranking system with an extensive list of methodology criteria and indicators, it is important to keep in mind, as for every other university ranking, its limitations and potential biases.
Review of global non-Academic University Rankings
As mentioned in a previous article, non-Academic University Rankings adopt a ranking methodology that does not focus mainly on academic indicators but chooses other types of indicators (i.e. web metrics) that are considered to be a good proxy to appraise and rank universities' popularity and academic reputation. Some of the most well-known global non-Academic university rankings, listed in order of the first year of publication, include:Webometrics Ranking of World Universities 
Firstly published in 2004, the Webometrics Ranking of World Universities is a non-academic university ranking compiled and published twice a year by the Cybermetrics Lab, a research group affiliated with the Spanish National Research Council (CSIC). Webometrics also publishes regional university rankings including the ones related to continents, the Arab world and the BRICS (Brazil, China, India and Russia) and CIVETS (Colombia, Indonesia, Vietnam, Egypt, Turkey and South Africa) countries.
- Webometrics Ranking frequency -
This ranking is published twice a year, at the end of January and at the end of July.- Webometrics Ranking coverage -
The Webometrics Rankings include in excess of 31,000 higher education institutions from more than 200 countries (2023).- Webometrics Ranking methodology -
The rankings are based on 3 indicators:1) Visibility: number of external networks (subnets) linking to the institution's webpages sourced from Ahrefs and Majestic (50%)
2) Transparency: number of citations from the top 310 authors of each institution (excluding the top 30 outliers) sourced from Google Scholar Profiles (10%)
3) Excellence: number of papers amongst the top 10% most cited in each one of all 27 disciplines of the full Scimago database (40%)
The Webometrics Ranking algorithm focuses 50% on university website link popularity (non-academic indicators) and 50% on citations (academic indicators). The presence of both academic and non-academic indicators makes the Webometrics Ranking a sort of hybrid university ranking that could fit in the Academic University Rankings category as well; the fact that 50% of the ranking algorithm is based on non-academic indicators and that the academic indicators component rely exclusively on bibliographic metrics (i.e. citations) made us lean towards including the Webometrics Ranking under the non-Academic University Rankings category; we might create an ad-hoc hybrid category in the future to better suit the Webometrics type of university ranking.
In regards to the visibility indicator, it is worth noting how the Webometrics Ranking has chosen the count of external subnets (instead of domains or external links) pointing to the institutions' websites in order to minimize low-quality/spammy inbound links which could undermine the significance of the highly weighted (50%) visibility ranking component.
- Webometrics Ranking criticism -
a) Methodology concerns: firstly, some have argued that the highly weighted (50%) non-academic visibility component of the Webometrics Ranking is not a reliable proxy or indicator of the quality of education, research or teaching at a particular higher education institution.Secondly, the choice of external networks (subnets) counts as a visibility indicator, despite being able to minimize the inclusion of low-quality/spammy inbound links, it is not a guarantee to filter and exclude all spammy links coming from low-quality subnets. This can jeopardize the accuracy of the data, especially in case of unethical behavior from those university webmasters who could try to artificially manipulate and inflate the total count of inbound links coming from different subnets in order to achieve a better ranking.
Thirdly, the accuracy of the visibility data depends on the level of maintenance and update of the dataset of over 31,000 official institutions domains included in the Webometrics Ranking; domains, especially in such a large dataset, can sometimes expire/change when higher education institutions cease to exist, merge, change their name, rebrand or simply decide to change their official web presence and start from scratch with a new domain (for example the well-known University of Sydney has changed its official domain name from usyd.edu.au to sydney.edu.au); the choice of the Webometrics Ranking publisher not to disclose in their website which domain has been used to appraise each institution's visibility prevents any third party to verify the freshness, up-to-dateness and, ultimately, accuracy of such a large dataset of domains.
Fourthly, there is no mention of whether the visibility indicator takes into consideration, in the total count of external networks, those subnet links that point to former domains adopted by each institution; if the former institutional domains are excluded, the total count of subnets would not represent the proper appraisal of the total historical visibility of the institution (in the case of the University of Sydney, for example, it would only count the total subnets links pointing to the new domain sydney.edu.au adopted from 2011 and exclude all subnets links still pointing to the former domain usyd.edu.au adopted from 1996 to 2010). According to uniRank, which researches and keeps a record of former institutional domains names, approximately 3,400 out of 13,800 (25%) higher education institutions have, for any of the several reasons mentioned above, one or more former domains adopted in the past; a much larger occurrence is expected in the Webometrics dataset of over 31,000 domains.
Fifthly, the Webometrics Ranking, similar to other university rankings that take into consideration research output and citations as indicators, could be biased towards English-language institutions. This bias may disadvantage institutions in non-English speaking countries that may produce high-quality research but are less likely to publish in English-language journals.
Lastly, only a small portion (possibly in the order of few thousand) of the large dataset of more than 31,000 universities included in the Webometrics Ranking would be included in the Google Scholar and Scimago databases. That would leave the great majority of higher education institutions ranked only by the visibility component with all its limitations explained above.
a) Limited Scope: the Webometrics Ranking only includes higher education institutions that have an online presence, which may exclude smaller or less well-known institutions that are making important contributions in their respective fields but, even if very rare, do not have an official web presence.
Overall, the Webometrics Ranking, being the largest global university ranking available to this date, is a well-established hybrid university ranking system that tries to fill the gap left by academic university rankings in terms of the number of covered higher education institutions. It is important to keep in mind, as for every other university ranking, its limitations and potential biases.
uniRank World University Ranking 
Firstly published in 2005, the uniRank World University Ranking is a non-academic university ranking compiled and published twice a year by the publisher of the uniRank website. uniRank also publishes regional and specialized university rankings including the ones related to continents, countries that share the same spoken language (English, Spanish, Arabic), religiously affiliated institutions and, based on a different ranking methodology, social media rankings.
- uniRank Ranking frequency -
This ranking is published twice a year, at the end of January and at the end of July.- uniRank Ranking coverage -
The uniRank Rankings include 13,840 higher education institutions from 200 countries (2023) that meet the following requirements:a) are officially recognized, licensed and/or accredited.
b) are officially licensed or authorized to grant at least four-year undergraduate degrees (Bachelor's Degrees) and/or postgraduate degrees (Master's and Doctoral Degrees).
c) provide higher education courses mainly in a traditional face-to-face learning format delivered through on-site facilities.
- uniRank Ranking methodology -
The rankings are based on 4 indicators:1) Majestic Referring Domains with a minimum Trust Flow (55%)
2) Similarweb Global Rank (35%)
3) Moz Domain Authority (5%)
4) Majestic Trust Flow (5%)
The Majestic Referring Domains with a minimum Trust Flow indicator provides an understanding of the number of quality referring domains, filtering out low-quality/spammy inbound links, each higher education institution's root domain has.
The SimilarWeb Global Rank is a website traffic scoring method developed by Similarweb to determine a website's rank and based on a mix of estimations of a website's monthly unique visitors and monthly pageviews across desktop and mobile web traffic; it is therefore an indicator of both the traffic (monthly unique visitors) and engagement/interest (monthly pageviews) of a higher education institution domain.
The Moz Domain Authority (DA), is a search engine ranking score developed by Moz that predicts how likely a website is to rank in search engine result pages and based on dozens of factors; similar to the Google PageRank, the Moz DA web metric tries to appraise the authority (i.e. relative importance) of a domain based on link analyses.
Similar to the Moz Domain Authority, the Majestic Trust Flow is a score developed by Majestic that indicates the perceived trust of a domain based on the quality of backlinks that a domain receives.
- uniRank Ranking criticism -
a) Methodology concerns: firstly, the most important criticism of the uniRank Ranking is that the non-academic indicators adopted are not a reliable proxy of the quality of education, research or teaching at a particular higher education institution and mainly a proxy of web popularity.Secondly, the choice of referring domains with a minimum Trust Flow as an indicator, despite being able to better minimize the inclusion of low-quality/spammy inbound links than the choice of the referring subnets, is not a guarantee to filter and exclude all spammy links and depends on the subjective choice of the minimum Trust Flow threshold as a parameter of quality of inbound links.
Thirdly, despite uniRank actively researches and keeps a record of most former institutional domains (approximately 25% of institutions in the uniRank dataset have one or more former domains) to properly appraise the total historical web visibility of each higher education institution, there is no guarantee that some former domains have been missed and not taken into account.
Lastly, the adoption of the Similarweb indicator may disadvantage higher education institutions in countries with a low internet penetration rate, which would cause lower traffic and engagement metrics or those few institutions that do not have their institutional domain name yet included and appraised by Similarweb due to lack of enough data.
a) Limited Scope: similar to Webometrics, the uniRank Ranking only includes higher education institutions that have an online presence, which may exclude smaller or less well-known institutions that are making important contributions in their respective fields but, even if very rare, do not have an official web presence. Moreover, the uniRank Ranking only includes higher education institutions that offer at least bachelor's degrees.
Overall, the uniRank Ranking, is a well-established non-academic university ranking system that tries to fill the gap left by academic university rankings, in terms of the number of covered higher education institutions around the world, by adopting indicators that are much easier to collect for a large dataset but potentially less reliable as proxies for appraising institutions academic performance. It is, therefore, important to keep in mind, as for every other university ranking, its limitations and potential biases.
Check this page for future reviews of other well-regarded global university rankings currently missing. Please feel free to send your feedback on this short guide and reviews on world university rankings. © uniRank
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