It is a well-known fact that academics worldwide face pressure to publish in prestigious English language journals. And the journal impact factor (IF) is the most widely recognized indicator of journal prestige and influence. Accordingly, many people choose which journals to publish in based largely on the IF.1
Calculation of IF
The IF is basically a ratio. The 2010 IF is calculated as follows: 2
All citations in 2010 to articles published in Journal X in 2009 and 2008
As you might have guessed, IFs for 2010 become available only in 2011 and so on. Journal IFs are calculated yearly and disclosed in the Journal Citation Reports (JCR) published by Thomson Reuters.
Use and misuse of IF
1. As an objective measure of journal prestige: There are a vast number of journals to choose from, and the journals’ IF provides an objective measure of the overall quality of work published in that journal. As a general rule, the higher the IF value of a journal, the more prestigious it is considered to be.
3. Academic evaluation: The IF is often used in the process of academic evaluations of researchers for tenure, grants, funding, etc. However, this use is incorrect because the IF is only meant to indicate the quality of an entire journal, not the quality of individual articles published in the journal.3
Beware while using the IF
When using the IF to compare or assess journals, it is important to understand the following points:4-5