Everything About Impact Factor

The Impact Factor helps you get a good assessment of the journals, especially when you encounter journals in the same field.

ISI Impact Factor is a measure of the relative importance of a particular journal within its scope of subject field.

Impact Factor is a quantitative metric for evaluating, comparing, and ranking scientific journals in different fields at the national or international level. Eugene Garfield created the Impact Factor in the 1950s, which is available through Thompson Reuters’ Journal Citation Reports.

• Content: Whether or not the journal’s content adds to existing knowledge.
• International Diversity: That is, the extent to which a journals’ topics and titles address international topics and issues.
• Publication standards: such as timely publication and clear paper and journal review process.
• Citation analysis: The amount of citations to journal editorial papers.

Impact Factor

Impact Factor is a quantitative metric for evaluating, comparing, and ranking scientific journals in different fields at the national or international level. Eugene Garfield created the Impact factor in the 1950s, which is available through Thompson Reuters’ Journal Citation Reports.

This metric reflects the total citations in a given year to all papers published in the past 2 years divided by the total number of articles and reviews published in the past 2 years; following you see the formula by which the impact factor is calculated:

The Impact Factor is calculated and published only for publications indexed in Thomson Reuters’s Web OF Science database. As such, only ISI journals have a true Impact Factor.

The impact factor was produced by Clarivate (formerly Thomson Reuters), published annually in June.

One of the best ways to find the impact factor of ISI journals is to use this link, where you are needed to enter and search the ISSN number in the relevant box to show the impact factor in recent years.

Impact Factor Pros & Cons

Since the impact factor has been created, many disputes have been made about it, and many have considered it unscientific and invalid. The impact factor is a general scale for evaluating a journal’s credibility, but caution should be exercised in using it:

Field diversity: We should not compare the impact factors of different fields and disciplines. For example, psychology is an interdisciplinary field, and many researchers use it, so the impact factor of its journals is often high. But for example, the nursing, because it is very specialized and only researchers of that field use it, its journals have a low impact factor.

Language Diversity: A very important and basic point is that the English ISI journal’s impact factor is higher than that of other languages.

Research Speed: In some disciplines, research speed is high, such as biology and immunology, but in other disciplines, including the humanities, an article can work over time. For these disciplines, the 5-year impact factor is usually more valid.

Free Access: Some journals publish their articles for free on the Internet, while other journals need others to pay for it. This can also affect the impact factor.

Types of Impact Factor

Impact Factor: Impact Factor is a measure of the relative importance of a particular journal within its scope of subject field.

Five-Year Impact Factor: This type of impact factor is more applicable to disciplines whose growth in scientific arena is slower, and the theories or papers in the field can find their true place over time. The 5-year impact factor is mostly used in the humanities. The 5-year Impact Factor is the average number of times articles from the journal published in the past five years have been cited in the JCR year (JCR is a trusted source for finding journal ranking; Journal Citation Reports (JCR) is an annual publication by Clarivate Analytics). It is calculated by dividing the number of citations in the JCR year by the total number of articles published in the five previous years.

Immediacy Index: This is the average number of times an article is cited in the year it is published and indicates whether a journal’s articles are considered as published, i.e. how quickly articles in a journal are cited. This index is mostly used for disciplines where the speed of science production is very high, such as biology or immunology. To calculate Immediacy Index, the number of citations to articles published in year X is divided by the number of articles published in that year. 

H-index: The h-index was invented in 2005 by Jorge Eduardo Hirsch, an Argentine-American professor of physics at the University of California, San Diego. Hirsch is an index that attempts to measure both the productivity and citation impact of the publications of a scientist or scholar by number. The h-index of a researcher is calculated by the total number of papers published (Np) and the number of citations (Nc) for each paper.

Although Impact Factor may be a good criterion for measuring the quality of journals, due to its limitations, it should not be used as a standard of comparison between disciplines. Besides, a 2-year publication window is too short for most journals, especially those which has not reached complete maturity.