The Best Global Universities ranking by U.S. News & World Report is an annual ranking of world universities. On October 28, 2014, U.S. News, which began ranking American universities in 1983, published its inaugural global ranking, assessing 500 universities in 49 countries. That first installment of the Best Global Universities Ranking was published without prior announcement, with U.S. News later clarifying that the rankings of that year were a trial balloon for the publication's entrance into the global university rankings field. After pre-announcing the rankings of next year, in 2016, the periodical formalized the global university rankings as part of its regular annual programming. Having made official the ranking methodology, it disclosed that it is based on 10 different indicators that measure universities' academic performance and reputations. The ranking has since been revised and expanded to cover 1,500 institutions in 81 countries and now includes five regional and 28 subject rankings. Employing 13 indicators and based largely on data provided by Clarivate, the U.S. News global ranking is methodologically different from its ranking of American institutions; global universities are rated using factors such as research reputation, academic publications, and the number of highly cited papers.