Students considering an overseas education first look at how well a university ranks, instead of the courses being offered or the size of the fees.
This was revealed by a study of nearly 500 students heading abroad.
The survey, conducted last year by international student recruitment agency IDP, also found that a university's reputation was especially crucial for students from China, followed by those from India and the Middle East. Rankings also mattered more to postgraduate students than to undergraduates.
Times Higher Education rankings editor Phil Baty, who presented the IDP survey findings at the World Academic Summit session held at Swissotel The Stamford, said it showed the growing influence of university rankings.
With international students and their families spending "five-figure sums of money" on an overseas education, "they are investing in their future, their CV (curriculum vitae), their brand for life", he explained.
Close to 15 per cent placed "attractive course structure and content" as the most important factor, while 14 per cent favoured "affordable tuition fees" first.
But a third of those surveyed said the international ranking and reputation of an institution was the most important consideration in choosing where to study. Coming in second was whether the school is internationally recognised by potential employers.
Mr Baty, however, warned students against relying just on rankings, such as the one released by Times Higher Education on Thursday.