Dear Editor,
The impact factor (IF) is frequently used as an indicator of the importance of a journal to its field. It was first introduced by Eugene Garfield, the founder of the Institute for Scientific Information.[1] Although IF is widely used by institutions and clinicians, people have widespread misconception regarding the method for calculating the journal IF, its significance and how it can be utilized. The IF of a journal is not associated to the factors like quality of peer review process and quality of content of the journal, but is a measure that reflects the average number of citations to articles published in journals, books, thesis, project reports, newspapers, conference/seminar proceedings, documents published in internet, notes, and any other approved documents (by Indian Council of Medical Research or similar body).[2]
Impact factor is commonly used to evaluate the relative importance of a journal within its field and to measure the frequency with which the “average article” in a journal has been cited in a particular time period. Journal which publishes more review articles will get highest IFs. Journals with higher IFs believed to be more important than those with lower ones.[3] According to Eugene Garfield “impact simply reflects the ability of the journals and editors to attract the best paper available.”[4] Journal which publishes more review articles will get maximum IFs.
Impact factor can be calculated after completing the minimum of 3 years of publication; for that reason journal IF cannot be calculated for new journals. The journal with the highest IF is the one that published the most commonly cited articles over a 2-year period. The IF applies only to journals, not to individual articles or individual scientists unlike the “H-index.” The relative number of citations an individual article receives is better evaluated as “citation impact.” In a given year, the IF of a journal is the average number of citations received per article published in that journal during the 2 preceding years. IFs are calculated each year by Thomson scientific for those journals that it indexes, and are published in Journal Citation Reports (http://www.thomsonreuters.com/products_services/science/science_products/a-z/journal_citation_reports/). For example, if a journal has an IF of 3 in 2008, then its papers published in 2006 and 2007 received three citations each on average in 2008. The 2008 IFs are actually published in 2009; they cannot be calculated until all of the 2008 publications have been processed by the indexing agency (Thomson Reuters). The IF for the biomedical journals may range up to 5-8%.[5] The IF of any journal may be calculated by the formula;
2012 impactfactor =A/B
Where A is the number of times articles published in 2010 and 2011 were cited by indexed journals during 2012. B is the total number of citable items like articles and reviews published by that journal in 2010 and 2011.
The calculation of IF for the journal where in a person has published articles is a contentious issue. Nevertheless, this have been already warned; “misuse in evaluating individuals” because there is “a wide variation from article to article within a single journal” therefore, “In an ideal world, evaluators would read each article and make personal judgments,” said by Eugene Garfield.[1]
References
1. Garfield E. The history and meaning of the journal impact factor. JAMA. 2006;295:90–3. [PubMed] [Google Scholar]
2. Esposito M. The impact factor: Its use, misuse, and significance. Int J Prosthet Dent. 2011;24:85. [Google Scholar]
3. Malathi M, Thappa DM. The intricacies of impact factor and mid-term review of editorship. Indian J Dermatol Venereol Leprol. 2012;78:1–4. [PubMed] [Google Scholar]
FAQs
Impact Factors are used to measure the importance of a journal by calculating the number of times selected articles are cited within the last few years. The higher the impact factor, the more highly ranked the journal. It is one tool you can use to compare journals in a subject category.
What are the limitations of journal impact factor? ›
The impact factor can be influenced and biased (intentionally or otherwise) by many factors. Extension of the impact factor to the assessment of journal quality or individual authors is inappropriate. Extension of the impact factor to cross-discipline journal comparison is also inappropriate.
What is the impact factor of my journal? ›
The impact factor indicates the average number of citations to articles published in a journal. You can use Journal Citation Reports (JCR), integrated with the Web of Science, to find impact factors.
What impact factor is considered good for a journal? ›
In general, an impact factor of 10 or higher is considered remarkable, while 3 is good, and the average score is less than 1. The very prestigious journal Nature had an impact factor of 69.504 in the year 2021.
Is an impact factor of 2.5 good? ›
The majority of journals, in fact, fall in the bracket of an IF of 1-1+. So, a journal with an IF of 2-2.5 would be considered having a higher impact than these journals. A journal with an IF of 5 or above would be considered high-impact, but note that these would be fewer in number.
How to use impact factor? ›
The Impact Factor is calculated by dividing the number of citations in the JCR year by the total number of articles published in the two previous years. An Impact Factor of 1.0 means that, on average, the articles published one or two year ago have been cited one time.
How to interpret impact factor? ›
An Impact Factor of 1.0 means that, on average, the articles published one or two year ago have been cited one time. An Impact Factor of 2.5 means that, on average, the articles published one or two year ago have been cited two and a half times.
What are the advantages of impact factor? ›
The sole advantage of IF is that it helps compare journals of the same field. It gives an idea of journal's relative importance and reputation.
Is impact factor a good measure of journal quality? ›
As long as academic journals belonging to the same field are compared, the impact factor of a journal helps determine its quality and relevance. This is a valuable grading tool that helps high-quality journals stand out in their field.
Which journal has the highest impact factor? ›
CA-A Cancer Journal for Clinicians
The credibility of a journal may be assessed by examining several key factors:
- Where is it indexed? Is the journal included or indexed in the major bibliographic databases for the field? ...
- What is its publishing history? How long has the journal been available? ...
- Is it peer-reviewed? ...
- What is its impact factor?
A good impact factor can vary by field, but in many scientific disciplines, an IF above 5 or 10 is often considered high.
What is an example of an impact factor? ›
According to Journal Citation Reports (JCR), an impact factor is a ratio focusing on original research. For example, if a journal has an impact factor of 2.5, this means in the indexed year each article published was cited on average 2.5 times in the previous two years in that journal.
What is a good h-index for a journal? ›
What is a Good H-Index? Hirsch reckons that after 20 years of research, an h-index of 20 is good, 40 is outstanding, and 60 is truly exceptional.
What is the impact factor of frontiers? ›
Journal Impact Factor and CiteScore
| Journal | 2022 Impact Factor | 2022 CiteScore |
|---|
| Frontiers in Physics | 3.1 | 3.8 |
| Frontiers in Physiology | 4.0 | 6.1 |
| Frontiers in Plant Science | 5.6 | 7.1 |
| Frontiers in Political Science | | 1.6 |
78 more rowsThis use of impact factors was summarised by Hoeffel in 1998: Impact Factor is not a perfect tool to measure the quality of articles but there is nothing better and it has the advantage of already being in existence and is, therefore, a good technique for scientific evaluation.
What journal has the highest impact factor? ›
CA-A Cancer Journal for Clinicians
Journal is the primary books of accounts. All transactions in a journal are recorded in a chronological order, that is, exactly when they occur. The journal is the most important books of entry as the correctness of all other accounting process depend on their accuracy.
