There are various organizations that publish global university rankings, and each has their own methodology and criteria for evaluating universities. However, most rankings consider factors such as academic reputation, research output, faculty/student ratio, international outlook, and alumni outcomes.

One of the most well-known global university rankings is the QS World University Rankings, which is published annually by Quacquarelli Symonds. The QS rankings evaluate universities based on six indicators: academic reputation, employer reputation, faculty/student ratio, citations per faculty, international faculty ratio, and international student ratio.

According to the 2022 QS World University Rankings, NUS and NTU are ranked among the top 20 universities in the world, with NUS ranked 11th and NTU ranked 12th. SUTD and SMU are also ranked among the top universities in Asia, with SUTD ranked 51-60 and SMU ranked 511-520 globally.

It is important to note that while university rankings can be useful for comparing universities and assessing their strengths and weaknesses, they should not be the only factor considered when choosing a university. Other factors such as program offerings, location, facilities, and student life should also be taken into consideration.