THE National University of Singapore is now the world's eighth best university, according to annual global rankings released on Tuesday.

It entered the top 10 of the latest Quacquarelli Symonds (QS) World University Rankings by Subject for the first time - becoming the first in Asia to do so. Statistics showed the NUS has courses in 12 subjects that were ranked in the world's top 10.

The institution was ranked 14th when the rankings began in 2011, before rising to 11th last year. It was Asia's best performing university each time.

London-based educational consultancy QS also publishes the overall World University Rankings, in which NUS was placed 25th last year. This year's overall rankings have yet to be released.

In the "by subject" ranking, varsities are rated according to their performance in 30 subjects, such as economics, psychology and law.

Cambridge University topped the list with 27 courses in the top 10, while Oxford University and the University of California, Berkeley, were in joint second with 23 subjects each.

NUS' highest rank came in communications and media studies, which was rated fourth best in the world.

Its statistics and material sciences came in fifth and sixth respectively, while its medicine faculty climbed a spot to reach the top 20 this year.

Overall, NUS maintained its performance across all disciplines - except psychology, which fell from 15th last year to 28th, and law, which dropped from 10th to 22nd. A QS spokesman said law's performance can be attributed to the introduction of a new indicator that measures the productivity and impact of journal publications.

The rankings are also based on responses from academics and employers around the world, as well as research citations. Altogether, 2,858 universities were evaluated and 678 ranked.

NUS provost Tan Eng Chye said the institution was "honoured". "This is a strong international recognition of NUS' strengths in humanities and languages, engineering and technology, sciences, medicine and social sciences," he said in a statement.

The Nanyang Technological University (NTU) also did well, improving in 13 out of 23 subjects. Its highest-ranked course was civil and structural engineering, which came in eighth.

NTU was also placed in the top 20 for five disciplines and top 50 in another seven. The results reaffirm the school's "rapidly rising status in the world of higher education", said NTU president Bertil Andersson.

QS head of research Ben Sowter said: "NTU started with a specialist base, with its emphasis on engineering and technology, but they are spreading out into other disciplines... In the next three to five years, it will be interesting to see what its medical school does with its partnership with Imperial College, London."

Other Asian institutions that performed well include The University of Tokyo and China's Tsinghua University.

ateng@sph.com.sg