Research Impact: Journal Impact

What is the "Impact Factor"?

A journal's Impact Factor measures citations relative to "citable items" published by that journal (usually articles) in the past two years. Articles in journals with high Impact Factors generally get cited more frequently than articles in low-impact journals.

The Impact Factor is part of JCR - Journal Citation Reports, a component of Web of Science. More information about the impact factor is available from Thomson Reuters. 

Are high-impact journals the best or top journals?

The Impact Factor and other metrics can be "rough approximations" of the top journals in a field, but the highest-impact journals are not always the most prestigious. We strongly recommend consulting with the Library's subject specialists, GWU faculty or other experts to identify appropriate journals, especially if you are preparing a manuscript for publication.

Some lists of "top" or quality journals are also found on our More Resources tab.

Other Journal Metrics from JCR

• 5-Year Impact Factor: Calculates the Impact Factor over a five-year period, instead of the (default) two years.
• Immediacy Index: Measures the citations to articles within the same year. Useful for determining how quickly articles are generally cited.
• Cited Half-Life: Measures the number of previous years that account for 50% of the articles cited in a particular journal. A long half-life indicates articles get cited for many years after publication.
• Eigenfactor Score: Calculates citations relative to citable items, similar to the Impact Factor, but assigns more weight to citations from articles in influential journals. For more information, visit the Eigenfactor.org website.
• Article Influence Score: Divides the journals Eigenfactor Score by the number of articles published in that journal. Provides an approximate "per-article" Eigenfactor Score. 

Additional Journal Metrics:

• SCImago Journal Rank (SJR): provides journal rankings based on data from Scopus. SCImago provides a detailed description of SJR (PDF).
• Google Scholar Metrics: Google ranks journals based on h5-index (the h-index for articles published in the previous 5 years).