The Journal Impact Factor is defined as all citations to the journal in the current JCR year to items published in the previous two years, divided by the total number of scholarly items (these comprise articles, reviews, and proceedings papers) published in the journal in the previous two years. A Journal Impact Factor of 1.0 means that, on average, the articles published one or two years ago have been cited one time. A Journal Impact Factor of 2.5 means that, on average, the articles published one or two years ago have been cited two and a half times. The citing works may be articles published in the same journal. However, most citing works are from different journals, proceedings, or books indexed in Web of Science Core Collection.
Steps to identify Journal Impact Factor for a journal in a category.
Example - Lets identify the high impact journalsfor the category biology.
1. Click 'Categories' to browse by category.
2. Select 'Biology & Biochemistry' category.
3. Select 'Biology' under the list of categories for 'Biology & Biochemistry'
4. Biology category has two editions SCIE and ESCI, select SCIE.
SCIE stands for "Science Citation Index Expanded" and is a part of the Journal Citation Reports (JCR) The SCIE provides a variety of metrics to help evaluate the impact and importance of scientific journals, including the journal's Impact Factor, which is a measure of the average number of citations per article in a particular journal over a specific time period. Other metrics provided by the SCIE include the Eigenfactor score, the Article Influence score, and the cited half-life.
ESCI stands for "Emerging Sources Citation Index" and is a part of the Journal Citation Reports (JCR). The ESCI is intended to help identify new and emerging research areas, as well as journals that are publishing high-quality research that has the potential to have a significant impact in their respective fie However, it is important to note that journals in the ESCI are not assigned an official Impact Factor, as this metric is only calculated for journals in the SCIE and SSCI.
5. Select 'Biology' SCIE to list the journals for this category and choose the journal 'Biological Reviews' which has the highest Journal Impact Factor.
6. For the journal 'Biological Reviews' the journal information along with the impact factor are:
In the above example 'Biological Reviews' has an impact factor of 14.355.