What is Impact Factor of a Journal?

What is Impact Factor of a Journal?

Eugene Garfield coined the term “impact factor” of a journal after forming the Institute for Scientific Information (ISI). Today, this organization has been reformed into what is well-known as Thomson Reuters, one of the biggest scientific publishers in the world. This publisher presents impact factors of all indexed journals in the booklet named “Journal Citation Reports.” Impact factor is basically a measure of the quality of a journal. The impact factor indicates the number of times articles are downloaded and cited from a journal. A popular journal has a very high impact factor. In general, subscription journals indexed by Science Citation Index (SCI) have very high impact factor.

In a journal, there are several related articles with informative content. How would you distinguish a particular article from several related articles in the journal? For this purpose, authors always check the number of times the article has been cited in research papers. This number is presented in Journal Citation Reports (JCR). In this way, scientists get to know the best journals in their respective field of study.

Let’s understand further how the visibility of the article increases with the number of citations it receives in research papers. That’s how we would understand the significance of impact factor. The impact factor reflects the quality of a journal because it represents the frequency of an article’s citation in research papers. This numerical value is presented in JCR.

If the number of citations received by an article is one, the impact factor of the journal is 1.0. If the number of citations received by an article are two and half times, the impact factor of a journal would be 2.5. Prestigious journals have high impact factors because their articles have been cited many times on an average. Low impact factor journals are not really preferred for publication. Now, let’s understand why we need journals with high impact factor in respective field of study. The volume of a journal and the frequency of a journal does not really signify the quality of a journal.

A big journal that publishes many articles would receive many citations as compared to an elite journal or niche journal that publishes selective number of articles. Then, how do we compare the quality of a big journal with that of a niche journal in a respective field of study, say, chemistry, physics, and biology. In fact, a number of niche journals are also interdisciplinary. For example, bioinformatics journals involve the study of biology as well as information technology, which is an emerging field pertaining to robotic surgery and genetic mapping, coding, etc.

The solution to this issue is journal impact factor. With this tool, we can compare the quality of a big journal with that of a small journal because it eliminates the use of absolute number of citations. Had that been the case, only big journals would have been favoured and small journals of interdisciplinary fields would not have survived. Impact factor also does not consider frequently published journals to be of higher quality as compared to those with just one or two issues in a year. Also, impact factor also negates the dominance of older journals over newer journals in a relative field of study. However, impact factor can be used to compare journals only of a respective field of study. That is, you cannot compare a mathematical journal’s impact factor with that of a chemistry journal’s impact factor. Both these fields are different and have different levels of citations, volume of papers, and frequency of publications. Impact factor is only an indicator of the quality of a journal, provided they are both mathematical or of chemical sciences.

By Nathan Baade