The National University of Singapore (NUS), which lost out to the Nanyang Technological University (NTU) in a worldwide ranking last year, has reclaimed its perch as Asia's top university this year.

In the Quacquarelli Symonds (QS) World University Rankings released this morning, NUS climbed from its 15th position last year to 11th this year, dislodging NTU, which moved back one rank to the 12th placing.

Singapore Management University was placed 500th. The Massachusetts Institute of Technology remains the world leader for the seventh consecutive year.

The World University Rankings employs six performance indicators to assess a university's strengths in research, teaching, employability and internationalisation.

QS said NUS has risen primarily due to improvements in its research performance. It improves its score for citations per faculty - which QS uses to measure institutional research impact - from 66.2/100 to 72.8/100.

NUS also maintains its position as the 11th in the world for academic reputation, an indicator that is based on the expert opinions of more than 83,000 academics across the world. It achieved the world's 18th-best score for employer reputation, which is based on the insights of more than 42,000 employers about the quality of an institution's graduates.

NUS, NTU and SMU scored 100/100 for international faculty ratio.

However, NTU retains its status as Singapore's strongest research institution, scoring 87.5/100 for citations per faculty - placing it 47th in the world.

Mr Ben Sowter, QS research director, said of Singapore's two leading institutions : "For a young nation of only 5.6 million people to be home to two of the world's top 15 institutions is remarkable. If they can embrace collaboration, there seems very little that NUS and NTU may not be able to achieve together."

On NUS, he said: "NUS has strengthened its year-on-year research profile to gain four places in this year's ranking... This iteration sees NUS re-establish itself as Asia's number one."

He also praised NTU for remaining among the world's top 15 despite being such a young university.

NUS president Tan Eng Chye said the university distinguished itself in the areas of academic as well as employer reputation, and continues to ramp up its research performance.

Elaborating on NUS' plans, he said: "The future of work in Singapore and around the world is changing rapidly. More than ever, universities around the world need to bring distinctive value to the communities that we serve."

NTU president Subra Suresh said: "NTU Singapore is immensely proud to be placed among the world's very best in the top 12, although it is the youngest in that cohort."

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He added: "The other great story here is that Singapore is home to two universities in the top 12. We should be very proud that Singapore is punching well above its weight."

NTU also remained third in the Times Higher Education ranking of young universities under 50 years old, which was released last night.

Said Professor Suresh: "As the only Singapore university listed in the under-50 ranking, NTU is leading a new generation of young, agile and forward-thinking universities that are championing high-impact research and innovative teaching methods."

Hong Kong University of Science and Technology was placed top young university by Times Higher Education.