The impact factor is used to measure the importance of a journal by calculating the number of citations for selected articles in a particular year. It is defined as the number of citations in the current year to an item published in the previous two years, divided by the total number of the items published in those same two years. Therefore, the higher the number of citations or articles from a particular journal or impact factor, the higher the rank.
Importance of impact factor of the journal
- A quantitative indicator for the importance of the journal decides the reputation of the journal.
- Impact factors indicate the relative significance and influence of a particular journal within its field of research/discipline.
- It’s a dynamic index that changes based on citations and the number of papers annually.
- The essential basis of selection of a journal to authors as well as to the reader.
Calculation of impact factor
The impact factor can be calculated after completing a 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 cited articles over a 2-year period. The IF applies only to journals, not to individual articles or individual scientists.
The impact factor is calculated by considering all citations in 1 year to a journal’s content published in the prior 2 years, divided by the number of substantives, and scholarly items published in that journal in those same 2 years.
Example.
“X” Journal published 130 papers in 2020 and 190 articles in 2021 published and cited 1015 times in 2020 and 885 times in 2021, what is the impact factor of that journal?
Impact Factor of “x” journal = CITATION 2021+ CITATION 2020/PUBLISHED PAPERS 2021+ PUBLISHED PAPERS 2020
= 1015 + 885/130 + 90
= 15.83
Problems associated with the use of journal impact factors
- Journal impact factors are not statistically representative of individual journal articles
- Journal impact factors correlate poorly with actual citations of individual
- Review articles are heavily cited and inflate the impact factor of journals
- Long articles collect many citations and give high journal impact factors
Blog contribution by
Nishad Y
Master in Public Health
Epidemiologist, coGuide