# Michael S. Rosenberg’s Laboratory

Computational Evolutionary Biology & Bioinformatics

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

## specific impact s-index

The specific-impact s-index (De Visscher 2010) is designed to avoid the age-bias of other indices as well as not penalizing fields where citations may lag due to the speed of the publication process. It is designed to predict the total number of citations a set of publications will have at a time infinitely in the future, assuming exponential aging of the citation process. The s-index is a measure of the projected citation rate per publication (rather than the actual citation rate per publication). The practical definition is

$$S=\frac{C^P}{10\sum\limits_{i=1}^{P}{\left(1-e^{0.1\left(Y-Y_i\right)}\right)}}=\frac{\sum\limits_{i=1}^{P}{C_i}}{10\sum\limits_{i=1}^{P}{\left(1-e^{0.1\left(Y-Y_i\right)}\right)}},$$

where s is a measure of the citation rate per publication (divided by 10) projected to time infinity. The actual prediction of the total number of citations an author would have at time infinity would therefore be 10sP.

Years
19970.4203
19981.2980
19992.2896
20002.6124
20013.4607
20024.4604
20035.1310
20046.4703
20057.5271
20068.8433
20079.7616
200810.7364
200911.6234
201012.3335
201112.6678
201212.8578
201313.0643
201413.2702
201513.4194
201613.5501
201713.4378

## References

• De Visscher, A. (2010) An index to measures a scientist's specific impact. Journal of the American Society for Information Science and Technology 61(2):319–328.