Measuring Research Impact

This guide provides an introduction to the information and issues regarding researcher and journal impact

Measuring Author Impact

Traditionally, author impact has been assessed based on the number of published articles and frequency of citation by other researchers. For this reason, most authors maintain a thorough list of their publications and many track how many times other authors cite their work.

In addition to number of publications and citations, metrics can also account for recentness of publications, poorly or highly cited articles, and how long a given researcher has been publishing. Below are a few popular impact indices.

Standard indices do not account for journal, article, or citation reputation.

Author Impact Indices

The most widely used metric, h-index, identifies the highest number of an author's papers to have the same or higher number of citations. For instance, for an author to have an h-index of 7, he or she must have at least 7 publications with 7 or more citations.

Advantages

Direct comparisons can be made within disciplines
Single value used to measure quantity and impact

Disadvantages

Inaccurate for early-career researchers
Only articles indexed in Web of Science are used in calculations
- If a researcher publishes in a journal not indexed by Web of Science, the article and any citations to it will be excluded from the calculation
Does not account for articles that are very poorly or very highly cited works

Tools for h-index

Web of Science This link opens in a new window
- Enter the author's name in the top search box (i.e. Smith JP)
- Select Author from the drop-down menu on the right
- Click Search.
- Click on Citation Report on the right hand corner of the results page

Google Scholar Citations
- Select advanced search (drop-down arrow to the right of search box)
- Enter author's name, in quotes, in "Return articles authored by" field (i.e. "JP Smith")
- Click Search
- Select author from "User profiles" –or– locate an article in search results from correct author
- Click author's name
- Citation info will appear in sidebar on right
Scopus Author ID Free Lookup
- Enter author last name and first name or initial
- Click search
- Select correct author from results

G-Index, another widely used measure, is calculated as the largest number n of highly cited articles for which the average number of citations is at least n. G-index adds more weight to highly cited publications and is considered by some to be more effective than h-index.

Advantages

Takes into account highly cited works
Makes more apparent the difference between authors' respective impacts.
- Inflated values help to give credit to lowly-cited or non-cited papers while still giving credit for highly-cited papers

Disadvantages

May not be as widely accepted as h-index

Created by Google Scholar and used in Google's My Citations feature, the i10-index indicates the number of publications by an author that have been cited at least 10 times by others.

Advantages

Simple and straightforward to calculate
My Citations in Google Scholar is free and easy to use

Disadvantages

Only used in Google Scholar

Tools for i10-index

Google Scholar Citations
- Select advanced search (drop-down arrow to the right of search box)
- Enter author's name, in quotes, in "Return articles authored by" field (i.e. "JP Smith")
- Click Search
- Select author from "User profiles" –or– locate an article in search results from correct author
- Click author's name
- Citation info will appear in sidebar on right

The m-quotient is aimed at early career researchers and helps to show prominence when enough time has not passed for authors to publish a high number of articles. M-quotient is calculated by dividing the h-index by the number of years an author has been publishing.

Advantages

Gives weight to highly cited works early in research career
Easy to calculate from h-index

Disadvantages

Only articles indexed in Web of Science are used in calculations
Does not account for articles that are very poorly or very highly cited works