Journal Impact Factors (JIF) and H-indexes

JIFs in general

Journal Impact Factors (JIF) are relatively simple bibliometric parameters of journals, based on citations received by the journal during recent years, but they are quite important as a measure of the (relative) scientific status of a journal.

While many derivatives and alternatives exist (based on larger time windows or other databases like e.g. Google Scholar), the official JIFs were originally created by – and are still defined by – the Journal Citation Reports (JCR) published by Clarivate Analytics ISI Web of Knowledge (ISI WoK). Although this database contains some 12,000 journals, many thousands of journals are not (yet) represented and thus do not feature an ‘official’ JIF.

Journal Citation Reports are published once a year, generally in June. Currently the most recent JIFs are those for the year 2021 (published in June 2022).

For more information on the uses and misuses of the JIF, see e.g. Schoonbaert D, Roelants G. Citation analysis for measuring the value of scientific publications: quality assessment tool or comedy of errors? Tropical Medicine and International Health 1996; 1: 739-752.

The Library & Information Science database contains thousands of references to JIFs and other bibliometric issues articles, the full text of which is available from the library.


To access Journal Citation Reports: use the ISI Web of Knowledge link > Top left, item 3 > Journal Citation Reports. The ISI WoK is not an open access database, but ITM does hold a paid subscription.

A list with the most current JIFs (currently relating to the year 2021) of some 700 journals that ITM staff have published in since 2005 can be found using the ITM JIFs quicklink on the left of this page.


Also the H-index (‘Hirsch’ index) is a relatively simple bibliometric parameter, basically indicating the volume of more or less highly cited publications for a specific author. A H-index of 28 indicates that the author has published at least 28 articles that have each been cited at least 28 times within the ISI Web of Knowledge system.

As with the JIF, many variants exist, but the ‘official’ H-index needs to be based on the ISI WoK data. Of course, H-indexes can also be calculated for groups of authors or for journals.

The Web of Science component of the ISI WoK contains a handy Create Citation Report feature that for your search results (e.g. articles by a specific author) automatically calculates a number of bibliometric parameters, including the H-index. Needless to say, this is a computer generated result that needs to be controlled manually for homonyms and other inaccuracies.

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