Scholarly Impact Metrics

Below are definitions of different impact metrics that you may see used when discussing scholarly impact for individuals. 

h-index

According to Elsevier, the h-index score is formulated based on “the number of papers (H) that have been cited, and how often, compared to those that have not been cited (or cited as much)” (What is a Good H-index?, n.d., para. 3). The h-index is the most widely adopted impact metric. It summarizes the impact of a scholar's career using a single number without any threshold. Below is a table from Elsevier that provides an example of how the h-index is calculated.

Click through this link for more information on h-index scores.

g-index

Considers all publications by a researcher to bolster papers with low citations by accounting for papers with a high number of citations, which are weighted more using the g-index. Used to improve upon the h-index by mitigating the insensitivity of the h-index to the number of citations received by highly cited papers but is not a replacement for the h-index.

Click through this link for more information on g-index scores.

Eigenfactor score

Calculates the number of citations a journal receives over five years. This score is used to “measure the importance of a journal throughout the scientific community and rewards large journals that publish a variety of topics” (Enago Academy, 2022, para. 1).

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Impact Factor

The average number of citations that publications in journals receive over the last two years to gauge the importance of both the journal and the articles within it (Waltman & Traag, 2020, pg. 3).

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Altmetrics

Short for “alternative metrics”, altmetrics measure the discussion of research and publications outside of typical academic circles, including “citations on Wikipedia and in public policy documents, discussions on research blogs, mainstream media coverage, bookmarks on reference managers like Mendeley, and mentions on social media networks such as Twitter” (What are Altmetrics?, n.d., para. 1).

Click through this link for more information on altmetrics.

PlumX Metrics

Assesses how “people interact with individual pieces of research output (articles, conferences proceedings, book chapters, and many more) in the online environment” by breaking down the metrics into five groups: citations, usage (clicks, downloads, video plays), captures (bookmarks, favorites), mentions (blogs, comments, news), and social media (share, like, comments) (About PlumX Metrics, n.d., para. 1).

Click through this link for more information on PlumX Metrics.