For the second year in a row, Cornell has been ranked No. 15 in the Times Higher Education-QS World University Rankings. The rankings are based on a mix of qualitative and quantitative measures, including cited research, staff to student ratio, international outlook and peer evaluations.

At the top of the 2009 list are Harvard University, Cambridge (U.K.), Yale, University College London (U.K.) and Imperial College London (U.K.).

The results are derived from surveys submitted by 9,386 academics and 3,281 major graduate employers. For a university to be considered for the ranking, it must operate in at least two of five major academic fields: natural sciences; life sciences and biomedicine; engineering and information technology; social sciences; and arts and humanities. It must also teach undergraduates.

Although Harvard is still ranked No. 1 -- for the sixth consecutive year ¬-- American dominance seems to be slipping, according to the publication.

While the United States still has the most institutions in the top 200, with a total of 54, it has lost five institutions from the top 100 and four have dropped out of the top 200 altogether. Rising on the list are institutions in Japan, Hong Kong, South Korea and Malaysia.

The rankings were established in 2004, with Cornell debuting at No. 23. Cornell moved up to No. 14 in 2005; 15 in 2006; 20 in 2007; and back to 15 last year.