Impact Factor and Other Ways of Assessing the Research Value of a Journal  

An Impact Factor is one measure of the relative importance of a journal or scientist to science and social science literature and research.

Each index or uses a different methodology and produces slightly different results, revealing the importance of using several sources to judge the true impact of a journal's or scientist’s work. 

Careful use of these impact data is essential, and should be based on a thorough understanding of the methodology used to generate impact factors. There are controversial aspects of using impact factors:

• It is not clear whether the number of times a paper is cited measures its actual quality.
• Some databases that calculate impact factors fail to incorporate publications such as textbooks, handbooks and reference books.
• Certain disciplines have low numbers of journals and usage. For this reason, one should only compare journals or researchers within the same discipline.
• Review articles normally are cited more often and therefore can skew results.
• Self-citing may skew results.
• Some resources used to calculate impact factors have inadequate international coverage.
• Editorial policies can artificially inflate an impact factor.