There are various ways to measure the impact of scholarly research and other types of publications.
Article-level metrics measure how often an article was cited in other publications.
Journal-level metrics measure the impact of scholarly journals and can be used in a variety of ways, including identifying key journals in a research field, which can be helpful when making manuscript submission decisions or evaluating journal quality.
Author-level metrics measure how frequently a specific author’s publications have been cited.
Altmetrics attempt to measure the impact of scholarship by using social media tools such as bookmarks, links, blog postings, inclusion in citation management tools, mentions and tweets to measure the importance of scholarly output.
Journal Impact Factor is the most commonly used journal-level metric. It is a measure of the frequency with which the average article published in a given scholarly journal has been cited in a particular year. These ratings are considered to reflect the importance of a particular journal in a field and take into consideration the number of articles published per year and the number of citations to articles published in that journal.
A journal's impact factor relative to other journals in its field is a more significant measure than where it ranks on the overall list of journal impact factors.
Journal Citation Reports is a tool used to obtain the impact factor for a journal (or journals). You can Ask Us! to search Journal Citation Reports for you; or, if you have Harvard access, you have the option to do your own search.
h-index is the most commonly used author-level metric.
h-index = number of papers (h) with a citation count ≥ h. For an example, an author with 15 publications cited 15 or more times has an h-index of 15 (assuming the 16th-most cited paper has fewer than 16 cites).
Jorge Hirsch, the developer of h-index, in his 2005 paper introducing the concept, also introduces another parameter (commonly referred to as m-index or m-quotient) which evaluates productivity of active researchers based on the number of years since the author's first publication:
A value of m ≈ 1 (i.e., an h index of 20 after 20 years of scientific activity), characterizes a successful scientist.
A value of m ≈ 2 (i.e., an h index of 40 after 20 years of scientific activity), characterizes outstanding scientists.
A value of m ≈ 3 or higher (i.e., an h index of 60 after 20 years, or 90 after 30 years), characterizes truly unique individuals.
Web of Science can be used to calculate your h-index. You can Ask Us! to use Web of Science to calculate your h-index for you; or, if you have Harvard access, you have the option to do this on your own.
The free version of Scopus will also allow you to obtain your h-index simply by searching for yourself by name/affiliation.
Google Scholar has citation counts as well and can also be used to calculate your h-index. But, Google Scholar citation counts tend to be more liberal than Web of Science, as they include scholarly and non-scholarly works (including blog posts) in their citation counts. This will result in a higher h-index, but Web of Science's h-index calculation is more universally accepted.
