g-index

The g-index is an index for quantifying scientific productivity based on publication record. It was suggested in 2006 by Leo Egghe.

The index is calculated based on the distribution of citations received by a given researcher's publications:

Given a set of articles ranked in decreasing order of the number of citations that they received, the g-index is the (unique) largest number such that the top g articles received (together) at least g² citations.

In simple terms, this means that an author that produces n articles is expected to have, on average, n citations for each of them, in order to have a g-index of n. In this way, it is similar to the h-index, with the difference that the number of citations per article is not explicit.

The g-index has been characterized in terms of three natural axioms by Woeginger (2008). The simplest of these three axioms states that by moving citations from weaker articles to stronger articles, one's research index should not decrease.

The g-index is highly correlated with the h-index (Serenko 2010). However, these indices are conceptually distinct, and the g-index attempts to address shortcomings of the h-index. Like the h-index, the g-index is a natural number and thus lacks in discriminatory power. Therefore, Tol (2008) proposed a rational generalisation.

Tol also proposed a collective g-index.

Given a set of researchers ranked in decreasing order of their g-index, the g₁-index is the (unique) largest number such that the top g₁ researchers have on average at least a g-index of g₁.

See also

• h-index
• h-b index

References

• Egghe, Leo (2006) Theory and practise of the g-index, Scientometrics, vol. 69, No 1, pp. 131–152. doi:10.1007/s11192-006-0144-7
• Serenko, Alexander (2010) The development of an AI journal ranking based on the revealed preference approach, Journal of Informetrics, vol. 4, No 4, pp. 447–459. doi:10.1016/j.joi.2010.04.001
• Tol, R.S.J. (2008) A rational, successive g-index applied to economics departments in Ireland, Journal of Informetrics, vol. 2, pp. 149–155. preprint
• Woeginger, G.J. (2008) An axiomatic analysis of Egghe’s g-index, Journal of Informetrics, vol. 2, pp. 364–368. doi:10.1016/j.joi.2008.05.002