Research Impact Matters: Impact Metrics

  H-Index

The h-index (Hirsch index) measures the impact of a particular scientist taking into account the number of papers published and the number of citations received by these papers resulting in a single number rating. For example, a scholar with an h-index of 5 has published 5 papers, each of which has been cited by others at least 5 times.

G-Index

The g-index is calculated based on the distribution of citations received by a given researcher's publications, such that given a set of articles 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 g² citations. Hence, a g-index of 10 indicates that the top 10 publications of an author have been cited at least 100 times (10²). 

 i10 Index

The i10-index is the number of publications published by an author with at least 10 citations.

m-Index

The m-index is defined as h/n, where h is the h-index and n is the number of years since the first published paper of the author; also called m-quotient.

An article's impact may be measured using both traditional citation metrics or through non-traditional usage metrics, called Altmetrics.

Traditional Impact Metrics examine how many times an article has been cited in other journal articles.

Sources for these metrics include :

• Google Scholar
• Scopus
• Web of Science

New measures of scholarly and social visibility

Many scholars are now using alternate article-level metrics which include:

• Usage: Number of times an article has been viewed, accessed, or downloaded on a publisher's site or other repository.
• Captures: Number of times an article has been captured on peer recommender systems such as Mendeley.
• Social bookmarking and dissemination activity: Measures can include Facebook likes, LinkedIn shares, and tweets.
• Media and blog coverage: Mentions by the popular press and blogs.
• Discussion activity and ratings: Social media activity can indicate the article's merits, immediacy, and importance.

Journal metrics for measuring a journal's importance to its field

• Journal Citation Reports

  Journal Citation Reports provides citation data drawn from over 11,000 scholarly journals and important indicators (Impact Factor) of how frequently current researchers are using individual journals.

• SCImago

  The SCImago Journal & Country Rank is a portal that includes the journals and country scientific indicators developed from the information contained in the Scopus® database

• Eigenfactor

  Journals are rated according to the number of referring citations, with citations from highly ranked journals weighted to make a larger contribution to the eigenfactor than those from poorly ranked journals.

• Google Scholar Metrics

  Journals included in Google Scholar are ranked by their h5-index for citations logged by Google Scholar. Journals may be sorted and ranked by subject.

• Scopus

  Scopus provides a free journal ranking service using CiteScore.