Journal Impact Factor
ThemesJournal Impact Factor
What is this about?
A journal’s ‘Impact Factor’ (IF) gives an indication of journal influence. The IF is a measure of the number of citations divided by the number of published articles in a journal.[1]
It is calculated for an entire year, taking into account number of citations in that year to all items published in the previous two years, and divided with a number of scholarly items (article, review, proceedings paper) in the previous two years.[2] For example, the 2018 IF of a journal reflects the number of times all items published in the journal in 2016 and 2017 were cited in 2018, divided by the number of scholarly items published in the journal in 2016 and 2017.
- ↑ Garfield E. The history and meaning of the journal impact factor. Jama. 2006;295(1):90-3.
- ↑ Clarivate. Journal Citations Report Help: Glossary. Accessed: 2023-02-08. URL: https://jcr.help.clarivate.com/Content/jcr3-glossary.htm
Why is this important?
Impact factors are important because they provide an indication of quality of a scientific journal. The idea is that journals with higher IFs are read more frequently, have more of an impact within a field, and are of higher quality. They are also important because some academic institutions ask for publications in journals with high IFs for acquiring a PhD or advancement.[1] Journal IFs are calculated each year by Clarivate (former Thomson Scientific or Thomson Reuters) and published on Journal Citation Reports platform.
Impact factors, however, can be manipulated. Examples of practices that influence IF are self and cartel citations, limitations of citable items, acceptance of certain types of publications.[2] Self-citation is a practice of citing one’s own work, to artificially increase a number of citations. Citation cartel is a practice of mutual citing between journals to increase their IF.[3] Editors can also insist that newly submitted manuscripts cite some of the works already published in that journal. Journals can limit a number of citable items, and not include them in the IF analysis. For example, letter to editor is a type of publication that is often referenced, and journals get the citation. However, that type of publication is not considered a scholarly item and it is therefore not included in the IF formula, thus increasing the IF. Journals can also choose to accept more review articles, which are often cited more, and can increase their IF that way.
It’s also important to note that it takes at least three years to calculate IF of the journal, and IF cannot be calculated for new journals. Because of all this, IF should be used cautiously when determining the quality of a journal, and other bibliometric data should be considered before making the final decision.[4][5]
- ↑ Casadevall A, Fang FC. Impacted science: impact is not importance: MBio. 2015 Oct 13;6(5):e01593-15. doi: 10.1128/mBio.01593-15. eCollection 2015 Sep-Oct.
- ↑ Sharma M, Sarin A, Gupta P, Sachdeva S, Desai AV. Journal impact factor: its use, significance and limitations. World J Nucl Med. 2014;13(2):1450-147.
- ↑ Fister I, Perc M. Toward the Discovery of Citation Cartels in Citation Networks. Frontiers in Physics. 2016;4(49).
- ↑ Ioannidis JP, Boyack KW, Small H, Sorensen AA, Klavans R. Bibliometrics: Is your most cited work your best? Nature. 2014;514(7524):561-2.
- ↑ Time to remodel the journal impact factor: Nature. 2016 Jul 28;535(7613):466. doi: 10.1038/535466a.
For whom is this important?
What are the best practices?
The Embassy Editorial team, Iris Lechner, Rea Ščepanović, Marin Vidak, Romana Jadrijevic Lozancic contributed to this theme. Latest contribution was Feb 08, 2023
