Difference in the impact of open-access papers published by China and the USA

We analyze the impact of open-access (OA) articles published by China and the USA by using Web of Science (WoS) data covering a period of 5 years (2011–2015), five indexes (citation and four altmetric indexes), five disciplines, and three types of articles. With regard to article type, Type I papers are those wherein the authors are all from China or the USA. Type II are those in which the first author is from China or the USA. Type III includes those in which the first author is not from China or the USA. We found that the proportion of OA papers in WoS has been growing in recent years. In terms of citations and altmetric indexes, the mean value of the USA is larger than that of China in general; Type II articles possess the highest value among all papers in the USA, whereas Type III has the highest value in China. Compared with the scenario in citations, social sciences and humanities possess larger altmetric values in China and the USA. The correlation among indicators is similar for the OA papers from China and the USA. Generally, citations cannot effectively represent the altmetric indexes. The gap between China and the USA is the largest in the altmetric attention score and Type I, and the smallest in citations and Type III. Measuring the international impact of OA papers using only citations underestimates the gap between China and the USA.