# Michael S. Rosenberg’s Laboratory

Computational Evolutionary Biology & Bioinformatics

E-mail: msr@asu.edu
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## hi-index

The hi-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 hi = 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) Rank (i) Authors (Ai) 42 36 14 11 9 9 3 2 2 2 1 1 1 0 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 h = 6 3 3 3 2 4 1 4 4 1 1 4 2 1 4 2 1

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

Yearhi
19970.3333
19980.8000
19991.1250
20001.6667
20012.2500
20022.7222
20033.5217
20043.1026
20054.0238
20064.0179
20074.8983
20085.6406
20097.5571
20107.7838
20118.7792
20127.7553
20138.0865
20148.3252
20159.2480
20169.4961
20179.4961

## References

• Batista, P.D., M.G. Campiteli, O. Kinouchi, and A.S. Martinez (2006) Is it possible to compare researchers with different scientific interests? Scientometrics 68(1):179–189.