# Michael S. Rosenberg’s Laboratory

Computational Evolutionary Biology & Bioinformatics

E-mail: msr@asu.edu
← Back to introduction

## EM-index

The EM-index (Bihaari and Tripathi 2017) combines elements of the multidimensional h-index, the two-sided h-index, the iteratively weighted h-index, and the e-index. The EM-index begins by creating a vector (E) which is equivalent to the upper/excess half of the two-sided h-index, namely a series of h values calculated from the citation curve of just the core publications, stopping when one reaches only a single remaining publication, no citations remain, or all remaining publications have only a single citation. From this vector, EM can be calculated as:

$$EM=\sqrt{\sum\limits_{i=1}^{n}{E_i}},$$

where Ei and n are the ith element and length of E, respectively.

### Example

Publications are ordered by number of citations, from highest to lowest. After each step, Ei is substracted from the citations of the top Ei publications. All publications beyond the top Ei are ignored at subsequent steps.

Citations (Ci) Rank (i) Adjusted Citations (Ci) Rank (i) Adjusted Citations (Ci) Rank (i) Adjusted Citations (Ci) Rank (i) 42 36 14 11 9 9 3 2 2 2 1 1 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 E1 = 6 36 30 8 5 3 3 1 2 3 4 5 6 E2 = 4 32 26 4 1 1 2 3 4 E3 = 3 29 23 1 1 2 3 E4 = 2 27 21 1 2 E5 = 2 25 19 1 2 E6 = 2 23 17 1 2 E7 = 2 21 15 1 2 E8 = 2 19 13 1 2 E9 = 2 17 11 1 2 E10 = 2 15 9 1 2 E11 = 2 13 7 1 2 E12 = 2 11 5 1 2 E13 = 2 9 3 1 2 E14 = 2 7 1 1 2 E15 = 1

The sum of the 15 E values is 36. The EM-index is the square-root of this sum, thus EM = 6.0000.

YearEM
19971.0000
19981.7321
19992.8284
20003.1623
20016.0000
20026.8557
20037.4162
20047.7460
20058.7178
20069.8489
200710.6301
200811.5758
200912.6886
201014.2478
201115.1658
201215.4272
201315.8745
201416.5227
201517.1464
201617.7482
201718.2757

## References

• Bihari, A., and S. Tripathi (2017) EM-index: A new measure to evaluate the scientific impact of scientists. Scientometrics 112(1):659–677.