Researcher impact metrics examine various pieces of data about a researcher, their publications, and the patterns of their career. These metrics come in two main groups: qualitative measures like who do they publish with, who do they cite, how long have they been active in various fields of research, and quantitative measures that examine how and when their publications are cited. These are some common quantitative measures.
h-index or H-index: named for its inventor, physicist Jorge Hirst, this metric identifies a person's most cited articles and how often they have been cited. An h-index of 6 means: an author's six most highly-cited articles have been cited six times.
hi-index: The h-index has been criticized because it does not take into account that some papers are written by groups and some are written by individuals. The hi-index was created to identify individual contributions to group-authored papers. If a researcher commonly publishes with many co-authors, their hi-index would be lower than a person who typically authors papers alone.
hc-index: The h-index has been criticized because established researchers with more publications will always have higher h-indexes than newer researchers with few publications. The "contemporary" version of the h index -- hence the name, hc-- weighs recently published articles more heavily, so newer researchers are not disadvantaged.
i-10 index: created by Google Scholar, this indicates the number of academic publications an author has written that have been cited by at least 10 sources.
Calculating these quantitative metrics, or creating lists of information to use in qualitative analysis, requires having access to all publications authored by a researcher, and a complete list of every time these have been cited. There are no databases that include all publications ever written; there are no databases that track each citation.
The sources below will calculate or allow you to calculate some qualitative and/or quantitative researcher impact metrics, based on their knowledge of the articles authored by one person and the citations to these articles appearing in several thousand journals. You will find different h-indexes for the same researcher in these different products. If you are reporting this data to someone else, report the source where you found it, too.
If you are trying to calculate these metrics for yourself, it can be helpful to establish a consistent researcher ID or researcher profile on one or more platforms. Learn more about setting up and managing researcher IDs on the Scholarly Communication guide.
Because each discipline has its own unique patterns for publishing, it's not appropriate to compare researcher metrics across fields of study. There are different author order conventions, rules for when you can or cannot cite your own papers, and citing patterns in different disciplines that can affect these quantitative researcher impact metrics.