NROD98: Thesis in Neuroscience

Journal impact measures the importance or influence of a particular journal in a field or discipline and can help you decide which journals you should publish in. Journal impact metrics take into account the number of articles published per time period and the number of citations to articles published in that journal. They can help track citation patterns within journals and determine which journals are highly cited.

There are many factors that influence the impact of a journal and each tool may produce varying results depending on the scope of its database. For a more accurate picture of journal impact, use more than one tool and compare the results.

What is it?

The Journal Impact Factor (JIF) or Impact Factor (IF) ranks journals based on how many times a journal's “average article” is cited in a particular year. The calculation is based on a 2-year citation period, where a journal’s citations are divided by the total number of published citable articles. 

The 5-Year Journal Impact Factor calculates over a larger span of years. The 5-year span can be useful for subjects where articles take longer to accumulate citations. A publication’s 5-Year Journal Impact Factor will tend to be higher than its Journal Impact Factor when the wait between publication and peak citation is greater than two years.

Limitations

• Open to manipulation
  • Many scholars believe it is not the most effective way to measure a journal's impact
• Not all journals have a JIF
  • Not available for all journals and coverage varies by discipline; only calculates citations for publications indexed by Web of Science.
• Should not be used to compare journals across disciplines
  • Impact factors vary between disciplines
• Not an indicator for the value of individual articles or authors
  • The impact factor was created to show the impact of a specific journal, not a specific scholar. The quality and impact of an author’s work is separate from the impact of a journal

Tools Available

• InCites Journal Citation Reports (JCR) uses citation and article count to evaluate and compare journals in a field. It can help you understand how frequently researchers are using particular journals. The resource also tracks: 
  • Total citations
  • Journal Impact Factor 
  • Eigenfactor Score
  • Most frequently cited journals, highest impact journals, and the largest journals in a field

Adapted from the Journal Impact guide