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Boxer Library

Publishing Your Research

What are citation metrics?

Citation metrics are calculations of how much an article or journal is cited or mentioned in other research. There are many different citation metrics and it is important to note that publishers will often create citation metric systems. The citation metric landscape is always changing! Some commons ones that we will mention in this guide are:

  • H-index
  • Journal Impact Factor
  • Altmetrics
  • Field-weighted Citation Impact (FWCI)
  • SCImago Journal Rank (SJR)

This YouTube series from Hong Kong Baptist University is a great resource to help you understand citation metrics:

  Author Level Journal Level Article Level
H-index X X  
Journal Impact Factor   X  
Altmetrics X X X
Field-weighted Citation Impact (FWCI) X X  
SCImago Journal Rank   X  

Remember that each citation metric is based on the publications/citations within each database. For example, this means that if you get an author's h-index from Google Scholar it may be different than their h-index in Scopus because of differences in indexing between each database.

H-Index is an author level metric that was created by Jorge E. Hirsch (it is sometimes called the Hirsch index or Hirsch number). It attempts to measure both the productivity and the impact of an author's publications. More recently, journals also can have an h index. 

An h-index shows that an author or journal has published h articles that have been cited h or more times. This means that the higher the h-index the better.

 Graph that shows h-index is defined as the maximum value of h such that the given author/journal has published at least h papers that have each been cited at least h times.

Remember:

  • A good h-index score requires both a large output and a large audience of that output. This can mean that the h-index favors authors who publish more and publish on "popular" topics. An author who outputs fewer but lengthier formats, like books, would have a "bad" h-index even if their books are very influential.

Where can you find H-Index Scores?

Journal Impact Factor (JIF) was created by Eugene Garfield but is now published by Clarivate.

JIF is always based on the last two years of a journal's performance. The two-year JIF reflects the yearly mean number of article citations in a given journal. 

For example:

Impact Factor for 2018 = Citation counts for 2016-2017/Number of Publications for 2016-2017

The most recent JIF is always one year behind. So, in 2023 the most recent JIF you can find is for 2022. 

Image from the University of Denver University Libraries Citation Analysis & Bibliometrics Guide

Remember:

  • JIF is a controversial metric because a journal's IF can be heavily skewed if the journal has a small amount of highly cited papers.
  • Since JIF is now calculated and "owned" by Clarivate, the dataset they use to calculate these numbers are not publicly available and therefore not reproducible.

Altmetrics are non-traditional metrics because they do not only consider traditional citations and publications. Altmetrics calculates impact based on a diverse online research output and from a diverse set of sources such as social media, online news, and more.

Altmetric scores are based on the following categories:

  • Viewed - includes both downloads and HTML views
  • Discussed - mentioned on blogs, social media, Wikipedia, etc.
  • Saved - saved in citation managers and bookmarks
  • Cited - cited in other literature
  • Recommended - some platforms allow recommendation or ranking of papers

Below is an example of an altmetric "donut." The amount of color in the donut represents a higher level of attention from those sources.

Altmetric donut with different colors representing different sources

Image taken from Altmetric's "The donut and Altmetric Attention Score" page on 1/10/23

Remember:

  • Online attention does not necessarily indicate the quality of the work. Certain articles may get a lot of negative attention online due to poor quality or controversy.
  • Like any other metric, altmetrics can be gamed and authors can try to boost their score by self-mentioning, self-citing, and even buying mentions or likes.

Field-Weighted Citation Impact tries to account for the fact that researchers in certain fields have a greater number of output than researchers in other fields. This output discrepancy may be due to research culture differences (e.g. scholars in the humanities write more books than scholars in STEM, which take longer).

FWCI is calculated by comparing the number of citations received to the expected average # of citations:

  • A FWCI of 1 means that the article performed as expected for the global average
  • A FWCI above 1 means that the article performed better than the global average
  • A FWCI below 1 means that the article performed less than expected for the global average

FWCI is sourced directly from SciVal and is only available through Scopus.

SCImago Journal Rank (SJR) is a measures the number of citations received by a journal, as well as the prestige of the journals where the citations come from. If a highly ranked journal cites an article, that citation will get more weight than a citation from a journal that is less highly ranked. SJR creates the journal rankings.

Unlike many other citation metrics, the SJR website is freely available online.