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By Barbara Gastel | 20 October 2013
[This post is from Alejandra (Alex) Arreola-Triana, who teaches research writing in Mexico and translates AuthorAID materials into Spanish. Thank you, Alex! —Barbara]
Recently I attended a meeting held by CONRICYT, the Mexican Council of Science and Technology Information Resources. The meeting attracted scientists, journal editors, and librarians. It included talks about many interesting topics.
One topic was impact factor. In Mexico, and perhaps many other countries, universities and the government evaluate researchers’ work in part by noting impact factors of journals where the researchers publish.
The impact factor of a journal is the average number of citations per citable item in a certain period—usually 2 years. Research articles and review articles are considered citable items. Comments and letters to the editor are not.
Impact factors vary widely among fields. The narrower a field, the lower the impact factors of journals in it tend to be. However, this does not necessarily mean the journals are obscure! Also, the impact factor does not say how much a particular article was cited.
At the meeting, speakers discussed other metrics that help show how much influence a researcher’s work exerts. These include the following:
· Source Individual Impact per Paper (SNIP): Articles in some fields, such as life sciences, cite more references than those in others, such as mathematics. SNIP adjusts for these differences and thus aids in comparisons between fields.
· SCImago Journal Rank (SJR): In this metric, a citation in a more prestigious journal is given a greater value.
· H-Index: This metric reflects both how many papers a researcher has published and how many times those articles have been cited.
Measuring scientific impact is difficult, and no single metric fully portrays a researcher’s influence. For more information, including more metrics, please see “The Evolution of Journal Assessment” and our post about the San Francisco Declaration on Research Assessment.