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Author impact metrics are indicators used to evaluate the impact of the academic publications of an author, a lab or an institution.
They are based on the number of citations and the number of publications.
The most recognised author metrics is the h-Index.
G-index and i10-index are alternatives to h-index. Please note that many other author metrics exist, but most of them are quite difficult to analyse.
H-index (or Hirsch index), is the most used author metric. It was created by the physicist Jorge E. Hirsch in 2005 (Hirsch, J. E. “An Index to Quantify an Individual’s Scientific Research Output.” Proceedings of the National Academy of Sciences - PNAS 102.46 (2005): 16569–16572. Web.).
It is based on the number of publications and the number of citations.
Keep in mind:
The h-index measures the production and impact of a researcher or group of researchers (all being evaluated equally, whatever their rank on the publication)
H-indexes cannot be compared across disciplines, as they are affected by each discipline's citation traditions and methods
Different databases will give different h-index because of the coverage (years, kind of sources) of each database. According to Harzing, A. W., & Alakangas, S. (2016). Google Scholar, Scopus and the Web of Science: a longitudinal and cross-disciplinary comparison" Scientometrics, 106(2), 787-804, the average h-index for the Social Sciences is:
All citations are taken into account, whether positive or negative
The H-index corresponds to the number of articles (N) on a list of publications ranked in descending order by the times cited that have N or more citations.
If somebody has an h-index of 5, it means that 5 of his articles have been cited at least 5 times each.
Articles | Citations |
1 | 46 |
2 | 25 |
3 | 12 |
4 | 11 |
5 | 5 = H-Index |
6 | 4 |
7 | 2 |
8 | 1 |
Wikimedia Commons http://en.wikipedia.org/wiki/File:H-index-en.svg
Keep in mind:
Keep in mind:
Before consulting your h-indexes, do not forget that different databases will give different h-indexes because of the coverage (years, kind and quantity of sources) of each database:
Scholar Citations |
|
Publish or Perish (Free downloadable software for academic citations analysis) |
|
Scopus Author Profile (Elsevier) |
|
Web of Science - Social Sciences Citation Index (Bibliographic database) |
|
"G-index is introduced as an improvement of the h-index of Hirsch to measure the global citation performance of a set of articles. If this set is 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" (Egghe, L., “Theory and practice of the G-index”. Scientometrics, vol. 69, no. 1, (2006), pp. 131–152).
Keep in mind:
The i10-index was created by Google Scholar (Google Scholar Blog, 2011):
i10-Index = the number of publications with at least 10 citations
Keep in mind: