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 subtracted from the citations of the top Ei publications. All publications beyond the top Ei are ignored at subsequent steps.
Citations (Ci) | 57 | 26 | 16 | 12 | 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 |
E1 = 6 | ||||||||||||||||||
Adjusted Citations (Ci) | 51 | 20 | 10 | 6 | 5 | 4 | ||||||||||||
Rank (i) | 1 | 2 | 3 | 4 | 5 | 6 | ||||||||||||
E2 = 5 | ||||||||||||||||||
Adjusted Citations (Ci) | 46 | 15 | 5 | 1 | 0 | |||||||||||||
Rank (i) | 1 | 2 | 3 | 4 | 5 | |||||||||||||
E3 = 3 | ||||||||||||||||||
Adjusted Citations (Ci) | 43 | 12 | 2 | |||||||||||||||
Rank (i) | 1 | 2 | 3 | |||||||||||||||
E4 = 2 | ||||||||||||||||||
Adjusted Citations (Ci) | 41 | 10 | ||||||||||||||||
Rank (i) | 1 | 2 | ||||||||||||||||
E5 = 2 | ||||||||||||||||||
Adjusted Citations (Ci) | 39 | 8 | ||||||||||||||||
Rank (i) | 1 | 2 | ||||||||||||||||
E6 = 2 | ||||||||||||||||||
Adjusted Citations (Ci) | 37 | 6 | ||||||||||||||||
Rank (i) | 1 | 2 | ||||||||||||||||
E7 = 2 | ||||||||||||||||||
Adjusted Citations (Ci) | 35 | 4 | ||||||||||||||||
Rank (i) | 1 | 2 | ||||||||||||||||
E8 = 2 | ||||||||||||||||||
Adjusted Citations (Ci) | 33 | 2 | ||||||||||||||||
Rank (i) | 1 | 2 | ||||||||||||||||
E9 = 2 |
The sum of the 9 E values is 26. The EM-index is the square-root of this sum, thus EM = 5.0990.
History
Year | EM |
---|---|
1997 | 1.0000 |
1998 | 1.7321 |
1999 | 3.7417 |
2000 | 4.1231 |
2001 | 5.0990 |
2002 | 5.6569 |
2003 | 7.0000 |
2004 | 8.4853 |
2005 | 10.1489 |
2006 | 11.7047 |
2007 | 13.5647 |
2008 | 15.3948 |
2009 | 16.7033 |
2010 | 18.2483 |
2011 | 19.3907 |
2012 | 20.7364 |
2013 | 21.9089 |
2014 | 22.8254 |
2015 | 23.8328 |
2016 | 25.1197 |
2017 | 26.4386 |
2018 | 27.7308 |
2019 | 28.7228 |
2020 | 29.4618 |
2021 | 30.0333 |
2022 | 30.7734 |
2023 | 32.6343 |
2024 | 34.6843 |
References
- Bihari, A., and S. Tripathi (2017) EM-index: A new measure to evaluate the scientific impact of scientists. Scientometrics 112(1):659–677.