Journal Impact Factors (JIFs) are one of the more commonly used journal level metrics. Generated by Clarivate's Journal Citation Reports (JCR), they are typically used in an effort to represent the impact of a journal.

JIFs are a journal level metric.

JIFs are calculated by taking the number of citations in a given year to articles published in the journal within the 2 preceding years, divided by the total number of citable publications published in the journal within the 2 preceding years.

Note: JIFs are only available for journals indexed in Web of Science. Additionally, JIFs will be based only on citing publications in Web of Science. (i.e., citations from publications that are not in Web of Science will not be factored into JIFs).

For example, The Journal of Excellent Examples (JEE) has a JIF of 3 in 2020. This would mean that articles published in the JGE in 2018 and 2019 were cited an average of 3 times each in 2020.

JIFs are created by Journal Citation Reports (JCR). You can find JIFs in both JCR and Web of Science.

Finding a journal's JIF in Journal Citation Reports (JCR)

1. Go to Journal Citation Reports
2. Enter the journal name into the search bar
3. If the journal has a unique name you might be automatically taken to the journal's JCR page. If not, look for the journal on your results page, and then click the title of the journal to go to the journal's JCR page
4. Scroll down until you see the heading "Journal Impact Factor"
5. The Journal Impact Factor (JIF) should display on the left

Finding a journal's JIF in Web of Science 

1. Go to Web of Science
2. From the dropdown to the left of the search bar, select "Publication Title"
3. Enter the name of the journal into the search bar
4. Look for the journal in your results list
5. Click the name of the journal in one of the citations
6. The Journal Impact Factor should appear on the left

Like any impact metric, JIFs have their limitations. Some of these limitations include:

• Largely limited to English and U.S. based journals
• Does not factor in journal productivity
• May be skewed by citation outliers (e.g., a single article may receive the vast majority of citations)
• Not all citations are "good" citations (e.g., Article A may cite Article B to reject Article B's findings)
• Does not exclude self citations
• What qualifies as a "good" JIF differs by field
• Does not take into account social impact (e.g., an article trending on Twitter)
• Due to large dataset (and lack of transparency in article-level citation metrics), difficult to replicate
• Like all impact metrics, vulnerable to gamification (e.g., citation cartels)

For an overview of JIFs and their limitations, see:

• Garfield E. The history and meaning of the journal impact factor. JAMA. 2006;295(1):90-93. doi:10.1001/jama.295.1.90.

• Laccourreye O, Maisonneuve H. The impact factor in peril? Eur Ann Otorhinolaryngol Head Neck Dis. 2019;136(1):1-2. doi:10.1016/j.anorl.2018.10.013.

• Wouters P, Sugimoto CR, Larivière V, et al. Rethinking impact factors: Better ways to judge a journal. Nature. 2019;569(7758):621-623. doi:10.1038/d41586-019-01643-3.

• Murphy LS, Kraus CK, Lotfipour S, Gottlieb M, Langabeer JR 2nd, Langdorf MI. Measuring scholarly productivity: A primer for junior faculty. Part III: Understanding publication metrics. West J Emerg Med. 2018 Nov;19(6):1003-1011. doi: 10.5811/westjem.2018.9.38213. Epub 2018 Oct 18. PMID: 30429933; PMCID: PMC6225941.

For a succinct overview of JIFs and their limitations, see:

• Journal impact factor. Metrics Toolkit. Accessed April 8, 2022. https://www.metrics-toolkit.org/metrics/journal_impact_factor/

• San Francisco declaration on research assessment. Declaration on Research Assessment (DORA). Accessed April 4, 2022.  https://sfdora.org/read/

For a look into how JIFs can be gamed, see:

• Davis P. The emergence of a citation cartel. The Scholarly Kitchen blog. April 10, 2012. Accessed April 4, 2022. https://scholarlykitchen.sspnet.org/2012/04/10/emergence-of-a-citation-cartel/

• Oransky I. Ten journals denied  2020 impact factors because of excessive self-citation or "citation stacking." Retraction Watch blog. June 30, 2021. Accessed April 8, 2022. https://retractionwatch.com/2021/06/30/ten-journals-denied-2020-impact-factors-because-of-excessive-self-citation-or-citation-stacking/

• Falagas ME, Alexiou VG. The top-ten in journal impact factor manipulation. Arch Immunol Ther Exp (Warsz). 2008;56(4):223-226. doi:10.1007/s00005-008-0024-5.

• Kojaku S, Livan G, Masuda N. Detecting anomalous citation groups in journal networks. Scientific Reports. 2021 Jul;11(1). doi:10.1038/s41598-021-93572-3.