The Publisher has a responsibility to use measures of quality assessment to demonstrate the success of his journal. Journal performance metrics give an insight about the performance and establishes a benchmark for growth. These metrics assist to the researchers to take wise decision about the selection of an appropriate journal. These metrics are calculated using data from the most popular databases i.e. Scopus, web of science, ScienceDirect and google scholar.
Impact Factor
The concept of impact factor was developed by Eugune Garfield at the institute for scientific information which is now published by Thomson Reuter once a year. Journal’s impact factor is used to find out the frequency with which the average article in a journal has been cited in a particular timespan. It is a way to identify the impact of an article in terms of how often the article has been cited by the researchers. The greater number of citation gives more significance of the article in the respective discipline. Impact factor can be used to-
- Identify journals in which to publish
- Identify journals relevant to your research
- Identify the status of the journals
Reference: Eugune Garfield, PhD,” The history and meaning of the journal impact factor”, JAMA, 2006: 295(1): 90-93, doi:10.1001/jama.295.1.90
Journal Citation Report (JCR)
JCR provides the information about impact factor, immediacy index, publisher information etc. of more than 10,000 indexed journals in arts, humanities, sciences and social sciences. The Impact factor is calculated for the journal indexed by ISI web of science (Thomson Reuter).
Journal impact factor for a particular year x can be calculated by using the given formula:
Journal Impact Factor=Total number of citation of the articles published in year (x-1) and (x-2) in a journal/Total number of citable articles published in year (x-1) and (x-2) in the same journal
For example, The impact factor of a journal in 2016 would have been calculated on the basis of the data collected in 2014 and 2015. If journal published 100 articles in 2014 and 2015 and the articles were collectively cited 150 times, the journal impact factor would be 1.50. It means that on average the article published in that journal have been cited around one and half times.
- There is no such database that indexes all journals across the world.
Immediacy Impact
Immediacy index indicates the frequency of citation to the articles published in the current year. The difference between impact factor and immediacy index lies in the JCR year (considered timespan to calculate impact factor). Immediacy index is restricted to the current year. It can be calculated for current JCR year x as:
Immediacy Index= Total number of citation of the articles published in year (x) in a journal/Total number of citable articles published in year (x) in the same journal
This calculation provides an instant glimpse into the article impact. If an article published late in the year, then it’s not possible for that to earn any citation in that particular year.
Eigenfactor Metrics
Eigenfactor calculation is somewhat similar to journal impact factor except it is calculated over a period of 5 years and does not include self-citation. So the eigenfactor value for a JCR year is calculated by dividing the total number of citation received by the articles during recent 5 years by the total number of citable articles published in the journal during the same period. Additional points are to be considered in determining the eigenfactor value:
- If an article is referenced to another article in the same journal will be removed so no journal self-citation is allowed.
- A journal which is more cited by the researchers will influence the network more than the less cited journal.
If the eigenfactor value of a journal is 2, it means a researcher spent 2 percent of his time to read this journal.
Reference:
- Jevin D. West, Theodore C. Bergstrom, and Carl T. Bergstrom,” The Eigenfactor MetricsTM: A Network Approach to Assessing Scholarly Journals”, published in College & Research Libraries 2010.
- Bergstrom, C.T. 2007. Eigenfactor: measuring the value and prestige of scholarly journals. College and Research Libraries News 68 (5): 314–16 (May).
H-Index
The h-index is introduced by J. Hirsch in 2005 to quantify an individual’s scientific impact and productivity. A researcher has h index, if he/she has at least N publications in which h of N papers have at least h citations each and rest (N-h) papers have at most h citations each.
For example:
| Researcher | Total Publications | Total Citation | Citation Impact | h-Index |
| A | 1 | 20 | 20 | 1 |
| B | 10 | 200 | 20 | 10 |
| C | 10 | 200 | 20 | 6 |
According to the given table, researcher A has only one publication for which he has 20 citations so the h-index will be 1. In the case of researcher B and C, in spite of having same details researcher C has h-index = 6. It means that even he has published the same number of articles and received same citation count as researcher B, still, researcher C is having more citation around his 6 articles whereas rest publications are having at most 6 citations.
Reference: Hirsch JE.,” An index to quantify an individual’s scientific research output”, Proc Natl Acad Sci U S A. 2005;102:16569–16572.