Thematic and geographical biases in the mention of research articles by blogs and news in three altmetric providers

The results of this study have showed that the coverage of publications are biased in favor of articles authored by English-speaking scientists, specially authors with affiliations in the United States and the United Kingdom. Contrarily, publications from China and Japan are unrepresented. This geographical bias was already noticed in previous studies, which detected very low altmetric impact for Latin-American and Spanish publications. This bias in the coverage of publications could be attributable to two factors. One internal factor could be that these platforms tend to select more English-speaking media than from other countries or languages. The high proportion of American and British media in these products could explain that English-speaking publications are more mentioned in the altmetric providers. This claim is reinforced after the chi-square test, which has proved that media tend to cite more publications affiliated to the same country than other different. However, other external factor could be that English-speaking media are more interested in scientific news and they include more citations to research articles than other countries.

According to the thematic coverage, distributions are less biased and only Medicine and Psychology articles are more mentioned in altmetric providers than in the random sample. These differences could be due to these subjects are closely related to public health issues and with more presence in media. This fact is confirmed when it is analysed the thematic distribution of articles cited by blogs and news. Social Science (32.6%) and Health Science (25.5%) articles are the thematic categories most cited by General and Local-interest media.