The 20 best universities in the world, according to US News & World Report

US News is known for its national universities and liberal arts college rankings, which for the third year in a row named Princeton University and Williams College as the top schools in America. Harvard ranked second on the national universities list.

The global rankings have not changed significantly from last year's inaugural list, and American universities still dominate, taking 16 of the top 20 spots.

Also in the top 20 are three British universities and a Canadian university.

In calculating its global rankings, US News looked at characteristics that "focus specifically on schools' academic research and reputation overall," unlike in the undergraduate rankings, which include factors such as undergraduate admissions data and graduation rates.