Citation analysis counts the number of times an article is cited by other scientific articles and applies to both authors and scientific articles. This count, which is generally analyzed over a specific period, allows us to obtain the impact of a specific article or author. Currently, more and more scientific article databases include citation counts. However, there is no single tool that counts all existing citations. The most comprehensive and recognized tools are Scopus and Web of Science.

SCOPUS – It is one of the most comprehensive international scientific article databases, including thousands of journal titles, of which 1,800 are Open Access publications. It has the “View Citation Overview” functionality, where you can see the number of citations per article and consult bibliometric indicators, such as the h-index.

Web of Science – Database of bibliographic references that includes the following databases:

     Science Citation Index Expanded (1899-present);

     Social Sciences Citation Index (1956-present);

     Arts & Humanities Citation Index (1975-present);

     Conference Proceedings Citation Index- Science (1991-present);

     Conference Proceedings Citation Index – Social Science & Humanities (1991-present).

In Web of Science it is possible to see which articles were cited by a given article in the “Cited references” section or check how many times an article was cited and by whom in the “Times Cited” option. It is from the Web of Science that the impact factor of periodical publications is calculated, as well as other bibliometric indicators present in the Journal Citation Reports.

Google Scholar – This tool has the “Cited By” functionality, which allows you to consult the citations that a given document has received. However, it should be noted that Google Scholar's citation counting methodology includes documents published on the Web from a variety of sources.

Bibliometric indicators - authors

H-index – Created in 2005 by J. Hirsch, the h-index is an indicator to quantify the productivity and impact of researchers, based on their most cited articles. Calculates an author's scientific production by counting the largest number of articles, which have at least the same number of citations. We can, for example, consider that an author's h-index is 15, when he has at least 15 published articles, with at least 15 citations each. However, despite being one of the most used metrics, it has been criticized for its calculation formula, which leaves out highly cited articles.

Where can we find an author's H-index?

– Scopus

– Web of Science

– Google Scholar – my citations

Note: the H-index is calculated taking into account the articles indexed in each of the tools, so an author's H-index may vary from base to base.

Bibliometric indicators – scientific journals

Impact factor – It is one of the best-known indicators and can be consulted in the Journal Citation Reports. It measures the frequency with which the “average article” in a magazine was cited in a given period.

Scimago Journal Rank Indicator – It is available in SCImago Journal & Country Rank and is based on scientific journals indexed in Scopus. This indicator is a measure of the scientific influence of scientific journals that is based on the number of citations received by a journal and the importance or prestige of the journals from which these citations come.

Alternative metrics

Alternative metrics or “altmetrics” are metrics based on data obtained from social media platforms, blogs and bibliographic reference management platforms. As the name indicates, these are alternative metrics to traditional metrics, which aim to measure the impact of research, almost in real time. In this type of metrics, not only citations are counted, but also the number of downloads, views, mentions and references on the platforms mentioned above.

Where to find alternative metrics?

Nowadays, several platforms already make this data available, such as the Scopus bibliographic database (information available in the Metrics table) or the publisher Taylor & Francis (information available in the Metrics tab at the top of the articles).

As for the tools to extract this data, there are several tools that function as aggregators of these alternative metrics, namely:

Altmetric – is a commercial-based platform that quantitatively evaluates the impact of an article on the Internet. It uses databases, websites, blogs, social networks and newspapers as sources of information. It offers some free services.

Plum Analytics – is a commercial-based platform that develops metrics for various types of documents, such as articles, book chapters, datasets, presentations, etc. It offers some free services.

Impact Story – is an Our Research project, a non-profit organization, which develops open-source tools with the aim of contributing to the Open Access movement for scientific research. Aimed at researchers, it allows them to explore and share the impact of their research online.