In July 2022, I shared our plans to extend the Journal Impact Factor (JIF) to all journals in the Web of Science Core Collection from June 2023. This means that this year, journals from the Arts and Humanities Citation Index (AHCI) and the multidisciplinary Emerging Sources Citation Index (ESCI) in the Journal Citation Reports (JCR) will receive a JIF for the first time.
A reminder that there are two reasons for this development: Giving all quality journals a JIF will provide full transparency to each and every article and citation that has contributed to a journal's scholarly impact, helping to demonstrate its value to the research community. It will also help level the playing field for all quality journals including open access journals, recently launched or niche journals, or journals with a regionally focused scope and those from the Global South.
As a result of this development, a further 9,000 journals in the JCR will receive a JIF and benefit from an enhanced journal profile page for the first time. In addition, we will display the JIF to one decimal place, rather than the current three decimal places, to encourage users to consider other indicators and descriptive data in the JCR when comparing journals.
Category rankings in 2023 JCR release
This year we will continue to provide category rankings and assign JIF quartiles for journals indexed in the Science Citation Index Expanded (SCIE) and the Social Sciences Citation Index (SSCI) only.
We will also continue to provide separate rankings for the nine subject categories that are indexed in multiple editions. For example, Psychiatry is included in both SCIE and SSCI – Psychiatry journals in SCIE will continue to be ranked separately from Psychiatry journals in SSCI this year.
The move to display the JIF to one decimal place will result in more tied rankings. This will affect JIF quartile distributions as quartiles are calculated according to the number of rank positions in a given category, not simply the number of journals in a category divided evenly into four (Figure 1).
The quartile distribution has typically resulted in approximately 25% of journals contained in each quartile – as ties have been infrequent. However, with an increase in the number of ties the distribution will shift. Journals tied at the same rank cannot be split between two quartiles and with the increase in the number of ties we will see that some quartiles will contain a larger or smaller number of journals than in previous years.
The formula for calculating quartiles can be found here.
What will category rankings look like in 2024?
In next year's JCR release, we will add AHCI & ESCI journals to the category rankings in the JCR and assign them to JIF quartiles. We will no longer have edition-specific category rankings and instead, we will create a single ranking for each of our 254 categories that includes journals from all four editions (SCIE, SSCI, AHCI and ESCI). Once again, taking Psychiatry as an example, we will display a single Psychiatry ranking including journals indexed in SCIE, SSCI and ESCI.
In the case of AHCI, we will introduce rankings for the 25 unique arts and humanities-specific categories for the first time. There will be no ESCI-specific categories; all journals indexed within ESCI fall within the existing 254 subject categories in SCIE, SSCI and AHCI.
The inclusion of 9,000 additional journals from AHCI and ESCI in JIF category rankings will also affect overall rankings and quartile distributions next year.
Why are we taking a phased approach?
We are expanding the JIF to AHCI and ESCI and moving to a one decimal point display of the JIF this year and then introducing AHCI and ESCI journals to category rankings next year, in order to provide transparency on how each of these changes separately affect JIF rankings and quartiles.
This is the first in a series of updates and analyses of how the expansion of the JIF to more quality journals will translate to changes in rankings and quartiles in JCR and explain how users can use JCR filters to view rankings that only include journals from editions of interest. Bookmark this page and stay tuned for further updates.