Evolutionary Biological Data Science Laboratory

h_i-index

The h_i-index (Batista et al. 2006) is a simple correction of the h-index for multi-authored publications. This index is simply the h-index divided by the average number of authors in the core publications, or

$$h_i=\frac{h}{\frac{\sum\limits_{i=1}^{h}{A_i}}{h}}=\frac{h^2}{\sum\limits_{i=1}^{h}{A_i}}.$$If every publication in the core is solo-authored then h_i = h. This can be an extremely harsh correction. A single core publication with a large number of co-authors may skew the average and thus lower an author's impact factor tremendously. Use of the median rather than the mean might be a fairer approach.

Example

Publications are ordered by number of citations, from highest to lowest.

Citations (Ci)	47	26	19	15	11	10	4	3	2	1	1	1	1	0	0	0	0	0
Rank (i)	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
						h = 6
Authors (Ai)	3	3	3	2	1	4	4	4	1	4	2	1	1	4	2	1	1	1

The h-index is 6 and the sum of the authors for publications in the core is 16, thus h_i = 2.2500.

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