Author impact

Citation analysis

Citation counts measure the impact of an author by counting the number of times he or she is cited in another work. There are different ways to calculate this.


“The h-index is an author-level metric that attempts to measure both the productivity and citation impact of the publications of an author. The index is based on the set of the author's most cited papers and the number of citations that they have received in other publications. The index can also be applied to the productivity and impact of a scholarly journal as well as a group of scientists, such as a department or university or country." -from Wikipedia

The h-index is calculated using the total number of papers published by an author and the total number of times each of those papers has been cited. For example, an author with an h-index of 23 has published at least 23 papers with at least 23 citations to each of those papers.

Like most bibliometrics, the h-index is discipline specific, and average h-indexes vary widely from one subject area to another. Comparisons should not be made across disciplines or subject areas. 

Bibliometric databases

The three major bibliometric databases are Web of Science, Scopus, and Google Scholar. They allow you to easily track an author's impact by:

  • Total number of times cited
  • Average citations per article
  • h-index
  • Number of citations each year
  • Co-authors

Web of Science

Search Web of Science

Web of Science covers the STEM fields and includes the following indexes:

  • Social Sciences Citation Index (1956-present)
  • Science Citation Index Expanded (1900-present)
  • Biological Abstracts (1926-present)
  • MEDLINE (1950-present)
  • Zoological Record (1864-present)
  • Arts and Humanities Citation Index (1975- present)

When browsing it, consider:

  • Citations from books, dissertations and theses, patents, and technical reports are not included.
  • Some subject areas don't have much coverage, such as business and education.


Search Scopus

Scopus includes journals, conference materials, and book records in science, technology, medicine, social sciences, arts, and humanities. As of January 2016, it contains more than 60 million records, including publications since 1823 and patents. References are only included for records after 1996.

Scopus assigns each author a unique Author ID that can be used to locate more information.

See complete list of coverage.

Google Scholar

Search Google Scholar

In addition to scholarly journals, Google Scholar includes government and academic websites, conference papers, and patents. Google Scholar displays results according to the number of times a work has been cited. Google Scholar covers the STEM fields and social sciences, arts, and humanities. It is unknown exactly which indexes and websites Google Scholar includes in its results.

If you don’t already have a Google Scholar Citations profile, sign up to get the most out of it. And access Google Scholar through our website to connect directly with full text.

Use Publish or Perish to learn more about an author’s impact.

Other measures

The following factors provide additional evidence of research impact and might be relevant for competitive grant applications and academic promotions:

  • Conference publications
  • International engagement
  • Influence on industry, government, public policy, community, and cultural organizations
  • Successfully acquitted research grants and projects
  • Awards and prizes
  • Holdings in libraries
  • Partnerships, editorships, and research fellowships
  • Membership of a learned academy
  • Membership of a statutory committee
  • Patents
  • Research commercialization income