在細看每所大學之前，先看一下許多學生和家長在選擇大學時會考慮的因素之一-世界排行榜。

事實上排名只可以當作是指引，不能單靠排行榜來決定任何選擇。

目前最受歡迎而具影響力的排行榜是Academic Ranking of World Universities (ARWU)，QS World University Rankings (QS) 和Times Higher Education World University Rankings (THE)。每個排行榜使用不同的方法來確定排名，但大多傾向大學的研究績效而不是教學質量。因此，許多大學積極提升其研究以滿足排名系統的標準，例如僱用更多的研究人員，撰寫更多研究文章以在期刊上發表，並提高引文率 (citation)。引文率是研究績效的其中一項指標，在許多排行榜中引文率佔相當高的百分比。這對人文科學、哲學和歷史學等學科為主的大學帶來了不利條件，這些學科的研究有一半以上是在數年後也不會被引用的；而需要使用許多參考文獻的科學學科，如生物化學、醫學則有更高的引用率。

另一個部分排行榜引人咎病的原因，是其對問卷調查的依賴，QS和THE均使用學術聲譽調查 (Academic reputation survey) 並佔相當大的比例，這調查佔QS排行榜40%，佔THE排行榜33%。在問卷調查中，學者/教育工作者會被要求列舉一些目前在其專業領域內表現最佳的大學，但不能給自己工作的大學投票。不少人認為隨機地向一群教育工作者或其他與學術機構有關的人徵求意見並非可靠。

因此，在選擇大學時，我們不應過分聚焦於這些排行榜。你會不會認為香港城市大學在2020年QS上排名51，比長春藤聯盟的Brown University (#57)還高這現象有點奇怪? 選擇大學還是根據是否喜歡該校園、大學是否擁有喜歡的學科、該學科是否較出色等因素來做出決定，以某學科享負盛名的大學亦未必等於所有學系都是頂尖的。

以下是較受歡迎排行榜的最近期的排名方法，讓大家用作參考﹕

Academic Ranking of World Universities (ARWU)
– Quality of Education – Alumni of an institution winning Nobel Prizes and Fields Medals – 10%
– Quality of Faculty – Staff of an institution winning Nobel Prizes and Fields Medals – 20%
– Quality of Faculty – Highly Cited Researchers – 20%
– Research Output – Papers published in Nature and Science (For institutions specialized in humanities and social sciences this is not considered, and the weight is relocated to other indicators.) – 20%
– Research Output – Papers indexed in Science Citation Index-Expanded and Social Science Citation Index – 20%
– Per Capita Performance – Per capita academic performance of an institution – 10%

QS World University Rankings (QS)
– Academic reputation (Academic Survey) – 40%
– Employer reputation (Employer Survey) – 10%
– Faculty/Student Ratio – 20%
– Citations per faculty – 20%
– International faculty ratio – 5%
– International student ratio – 5%

Times Higher Education World University Rankings (THE)
– 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%
– Research (volume, income and reputation): 30%
– Reputation survey: 18%
– Research income: 6%
– Research productivity: 6%
– Citations (research influence): 30%
– International outlook (staff, students, research): 7.5%
– Proportion of international students: 2.5%
– Proportion of international staff: 2.5%
– International collaboration: 2.5%
– Industry income (knowledge transfer): 2.5%

U.S. News Best Global Universities Rankings
– Global research reputation – 12.5%
– Regional research reputation – 12.5%
– Publications – 10%
– Books – 2.5%
– Conferences – 2.5%
– Normalized citation impact – 10%
– Total citations – 7.5%
– Number of publications that are among the 10% most cited – 12.5%
– Percentage of total publications that are among the 10% most cited – 10%
– International collaboration – relative to country – 5%
– International collaboration – 5%
– Number of highly cited papers that are among the top 1% most cited in their respective field – 5%
– Percentage of total publications that are among the top 1% most highly cited papers – 5%