The Times Higher Education (THE) has been publishing World University Rankings since 2004, providing a definitive list of the world's best universities evaluated for five indicators — teaching, research, citations, international outlook and income from industry. Ranking first for 2017-18 is the University of Oxford, and the second is the University of Cambridge. In third place is the California Institute of Technology (CALTEC) in the United States.

Out of the five indicators for evaluation, international outlook accounts for 16 percent of the total, and half of this — 8 percent — is based on the ratio of international students. For this particular section of the indicator, the University of Luxembourg, Qatar University, and the University of Hong Kong are the top three. With regard to universities here in Japan, this indicator is the weakest.

Overall, the growth in the number of international students is remarkable. According to UNESCO data, the total number of international students in higher education was 2 million in 1999, but in 2014 it topped 4.3 million. And the number keeps growing.