Research Guides: Measuring Research Impact: Author Impact Metrics

Metrics for evaluating authors

What is H-index?

H-index (or Hirsch index), is the most used author metric. It was created by the physician Jorge E. Hirsch in 2005 (California University). It is based on the number of publications and the number of citations.

Keep in mind:

The same author h-index may vary from one database to another, depending on the coverage of each database
Co-publishing can elevate the h-index, because it does not take the order of authorship into account
Time helps to increase the h-index; young researchers generally have a low h-index
The subject area can affect the H-Index: a researcher who publishes on a trendy subject will have a higher h-index than another one who publishes on a niche topic
The language of the publication affects the h-index; publications written in English receive more citations
Open access publishing increases the visibility of articles and their chance to be cited
Promotion of publications (blog posts, academic social networking, preliminary research findings at conferences,...) helps to make articles more visible and increases their chance of being cited
H-index takes self-citations into account; some high h-indexes are due to self-citation abuses

Where to check your H-index?

Keep in mind:

Before consulting your h-indexes, do not forget that different databases will give different h-indexes because of the coverage (years, kind and quantity of sources) of each database:

Scholar Citations

A Google account is necessary to create a profile and consult your h-index or i10-inde x
This h-index tends to be higher than the one found in Web of Science, because of its coverage (web-based sources)
Updates
About Google Scholar metrics

by Microsoft Research

Create a profile to consult your h-index or g-index
Coverage (scholarly publications discovered and indexed by Bing)
Updated: unknown

Publish or Peris h (Free downloadable software for academic citations analysis)

Coverage (Google Scholar, Microsoft Academic Search, etc.)
Provider of h-index, g-index, total number of publications and citations and average citation per publication

Scopus Author Profile (Elsevier)

Coverage
Free access to author's h-index, total citations
Updated: daily

An AI-powered database, H-index is provided.

Web of Science

Coverage (from 1900 - present for some journals): less content than Scopus in the social sciences
Search by author name or researcher identifier (ORCID or ResearchID) and click on “create citation report” in the upper right corner
Citation report includes: h-index, visual presentation of publications per year and citations per year, total times cited, average times cited
Updated: weekly

How to calculate it?

The H-index corresponds to the number of articles (N) on a list of publications ranked in descending order by the times cited that have N or more citations.

If somebody has an h-index of 5, it means that 5 of his articles have been cited at least 5 times each.

Articles	Citations
1	46
2	25
3	12
4	11
5	5 = H-Index
6	4
7	2
8	1

Wikimedia Commons http://en.wikipedia.org/wiki/File:H-index-en.svg

"G-index is introduced as an improvement of the h-index of Hirsch to measure the global citation performance of a set of articles. If this set is ranked in decreasing order of the number of citations that they received, the g-index is the (unique) largest number such that the top g articles received (together) at least g²citations" (Egghe, L., “Theory and practice of the G-index”. Scientometrics, vol. 69, no. 1, (2006), pp. 131–152).

Keep in mind:

The g-index gives more weight to highly-cited articles (whereas the h-index is insensitive to it)
Someone's g-index will always be equal to or greater than the h-index

The i10-index was created by Google Scholar (Google Scholar Blog, 2011): i10-Index = the number of publications with at least 10 citations

Keep in mind:

It is only accessible from Google Scholar Citations (author profile, you need a Google account to manage your profile)
The i10-index is easy to calculate

What is citation count ?

It is the total number of times an author's work has been cited.

Keep in mind: Citation analysis as a qualitative measurement should be used cautiously, for the following reasons:

Citation rates and practices vary widely between disciplines. Citation analysis of scholars in one field should not be compared to those in another.

Where a scholar publishes can have a great impact on the analysis if the tools used to count citations do not index the publications where a scholarly work is cited. This is particularly true for those that publish in international journals, smaller regional or local publications, or in non-journal sources such as books.

Citation rates can be influenced by practices such as self-citation.

Where to check your citation counts?