The h-index is a quantitative value that measures the ratio of the number of publications and the number of citations from within a researcher. The index is based on a list of the number of researcher publications ranked in descending order according to the citation count. (Hirsh 2005)
The h-index captures research output based on the total number of publications and the total number of citations to those works, providing a focused snapshot of an individual’s research performance.
If a researcher has 20 publications each of which has at least 20 citations, their h-index is 20
The index refers to a specific field of research (for example in mathematics the h-index is low compared to the life sciences where the index in this field is high)
Self-citation - The larger the number of authors, the more the self-citations are and the value goes up.
Each database may determine a different h-index for the same individual as the content in each database is unique and different.
The index values are in the databases: