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Library Subject Guides

Scholarly Publication: Measuring Impact

An introduction to intellectual property, open access, current awareness, measuring impact for PBRF, and using the Research Repository.

Citation counts

Databases that provide citation counts include:

Links of Interest

Author Impact - The h-index

scattergraph showing h-indexThe H-index is a measure of the number of publications published by an individual and how often they are cited 

An author's h-index, or Hirsch index, is the number (integer) n for which the author has published at least n papers which have each been cited at least n times.  Eg

  • 5 papers cited 1, 2, 3, 4, 5 times: h-index is 3 (3 papers cited at least 3 times)
  • 5 papers cited 1, 1, 2, 2, 2 times: h-index is 2 (at least 2 papers cited 2 times)
  • 5 papers cited 1, 1, 1, 1, 20 times: h-index is 1 (at least 1 paper cited 1 time)


How to find your h-index

Scopus - Select author search or ORCID. click view Citation Report
Google Scholar  - Create a Google Scholar profile which will generate your h-index
Publish or Perish - Based on Google Scholar Metrics this free software can calculate a variety of author metrics
Microsoft Academic - re-activated in 2016, Microsoft's answer to Google Scholar

Journal impact factors

Impact factors attempt to measure the importance of a journal based on how often its articles are cited in the field.

Journal Impact Factor (JIF)

  •  Based on Web of Science. UC does not subscribe to Journal Citation Reports but JIF data can be viewed in Web of Science at article level. Reflects the average number of citations each article receives over 2 years.

SNIP (Source Normalized Impact Per Paper)

  • Measures the average citation impact of the publications in a journal. Corrects for differences in citation practices between scientific fields. Based on Scopus data. 

SciMago Journal and Country Rank (SJR)

  • Ranks journals indexed in Scopus from 1996. Key indicator is known as SciMago Journal Rank Indicator (SJR). Includes approx.20,000 journals in 313 subject specific categories


  • Developed by Elsevier in 2016 and based on Scopus data. Average citations received over the last 3 years. Not subject field normalized.


  • Uses Thomson Reuters data for approximately 12,000 journals.  Read the Eigenfactor FAQs

Google Scholar Metrics

  • Provides h5-index and h5-median for  the top 20 journals in 267 subject categories.



Obvious factors can heavily influence journal impact factors, such as journal title changes, or publishers gaming the system by requiring authors to cite articles from other journals by the same publisher.  However there are more systematic problems:

  • Review articles are often widely cited, so review journals tend to top the lists.
  • Citations can be based on a single publisher's dataset. Compare multiple tools.
  • Wide variations between different research fields inherent to the different patterns of publication in those fields.

What are altmetrics?

  • a measure of the amount of exposure based on web activity, including download counts, page views, mentions in news reports, social media, blogs,
  • altmetrics (alternative + metrics) are complementary to conventional article-level metrics like journal impact

What are altmetrics? (from

Scholars seek better ways to track impact online

Where to find altmetric measures?

Symplectic Elements - as well as standard metrics such as SNIP and SJR,  Elements provides Altmetrics e.g. number of times an output has been picked up by news outlets, tweets, blogs, Mendeley, CiteULike, Facebook etc

Ebsco databases (e.g PsycInfo, Business Source Complete) now include PlumAnalytics

Some journal web-sites also provide altmetric statistics