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.
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.