Evolutionary Biological Data Science Laboratory

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.

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