Research Impact

The journal impact factor (JIF) of an academic journal helps you determine the importance of a journal within its field. 

This number is calculated by dividing the number of current year citations indexed in the Web of Science Core Collection to the source items published in that journal during the previous two years.

For example, the journal impact factor of Analytical Chemistry is 8.008. This means, on average, articles published by this journal in the last two years have been cited 8 times. 

You can find a journal's impact factor and compare impact factors across journals in your field in Web of Science's Journal Citation Reports.

JIF is proprietary and there is a lack of transparency in how it is calculated by Web of Science. It has also been criticized for being skewed by a few high impact articles, only counting the most recent two years of citations, its broad definition of "citable items," and disciplinary differences (Larivière & Sugimoto, 2018). 

The h-index of a journal measures the frequency of citations from articles in a journal over time. A common metric is the h5-index, which measures how x number of publications have been cited x number of times in the previous 5 years.

For example, if the journal Science has an h5-index of 401, that means 401 articles have been cited 401 or more times in the past 5 years. This metric privileges more established journals and disciplines with high research productivity. 

You can find the h-index that is calculated with different datasets in Google Scholar, Scimago Journal Ranking, and Web of Science.

The Scimago Journal Ranking helps researchers compare the impact of journals in similar fields. This score is calculated by the average number of weighted citations in the selected year by the documents published in the selected journal in the three previous years. For example, if the journal Cell has a SJR rank of 26.494, this means it has recently been cited at a higher rate than lower ranking journals in the past 3 years. 

You can search for metrics on a specific publication, or use filters to see rankings by subject area. 

Journal metrics can be: 

• Influenced by interdisciplinarity, open access, and citation conventions in a particular discipline 
• Skewed by a few number of highly cited articles
• Biased toward English-language publications
• Limited to indexing in a particular database and citable materials
• Prioritized over qualitative measures of impact, especially during recruitment, tenure, and grant funding

Further Reading

Bohannon, J. (2016, July 6). Hate journal impact factors? New study gives you one more reason. Science. 

Kurmis, A. P. (2003). Understanding the limitations of the journal impact factor. The Journal of Bone & Joint Surgery, 85(12), 2449-2454.

Larivière, V., & Sugimoto, C. R. (2018). The Journal Impact Factor: A brief history, critique, and discussion of adverse effects. Springer Handbook of Science and Technology Indicators, 3-24.

You can also evaluate the quality of a journal based on its: 

• Editors and editorial board
• Peer review process
• Acceptance rate
• Publisher

Reference

"Assessing Journal Quality " by UNO Libraries, University of Nebraska at Omaha is licensed under CC BY-NC-SA 4.0