Compare methods

	m-Quotient (Hirsch m)	Contemporary h-Index	g-Index (Egghe)	hg-Index (Composite Hirsch-Egghe)
Field	Bibliometrics	Bibliometrics	Bibliometrics	Bibliometrics
Family	Process / pipeline	Process / pipeline	Process / pipeline	Process / pipeline
Year of origin	2005	2007	2006	2010
Originator	Jorge E. Hirsch	Antonis Sidiropoulos, Dimitrios Katsaros & Yannis Manolopoulos	Leo Egghe	Sergio Alonso, Francisco J. Cabrerizo, Enrique Herrera-Viedma & Francisco Herrera
Type	Career-length-normalized author impact rate	Age-discounted author impact index	Author-level cumulative-citation impact index	Composite author impact index
Seminal source	Hirsch, J. E. (2005). An index to quantify an individual's scientific research output. Proceedings of the National Academy of Sciences, 102(46), 16569-16572.	Sidiropoulos, A., Katsaros, D., & Manolopoulos, Y. (2007). Generalized Hirsch h-index for disclosing latent facts in citation networks. Scientometrics, 72(2), 253-280.	Egghe, L. (2006). Theory and practise of the g-index. Scientometrics, 69(1), 131-152.	Alonso, S., Cabrerizo, F. J., Herrera-Viedma, E., & Herrera, F. (2010). hg-index: a new index to characterize the scientific output of researchers based on the h- and g-indices. Scientometrics, 82(2), 391-400.
Aliases	Hirsch m-quotient, m-parameter, h-index per year	hc-index, time-weighted h-index, age-decayed h-index	Egghe g-index, Egghe index, g index	Alonso hg-index, hg index, composite h-g index
Related	3	3	3	3
Summary	The m-quotient, defined by Jorge Hirsch in the same 2005 paper that introduced the h-index, normalizes an author's h-index by the length of their scientific career. Because the h-index can only grow over time and never decreases, raw h-values systematically favor senior researchers and make it unfair to compare early-career scientists with established ones. The m-quotient divides the h-index by the number of years since the researcher's first publication, yielding a rate of impact accumulation per year. Hirsch proposed rough benchmarks on this scale, suggesting that a sustained value near 1 characterizes a successful scientist, near 2 an outstanding one, and near 3 a truly exceptional figure, making the m-quotient a tool for comparing researchers at different career stages.	The contemporary h-index, introduced by Sidiropoulos, Katsaros, and Manolopoulos in 2007, modifies Hirsch's h-index to reward recent scientific activity over old laurels. The plain h-index never decreases and treats a citation earned decades ago the same as one earned last year, so a researcher who has stopped publishing can coast on an aging body of work. The contemporary index assigns each paper an age-discounted score, multiplying its citation count by a factor that shrinks as the paper grows older, and then applies the usual h-index ranking criterion to these scores. The result distinguishes currently active, recently impactful researchers from those whose reputation rests on distant achievements.	The g-index, introduced by Leo Egghe in 2006, is an author-level bibliometric indicator designed to repair a structural weakness of Hirsch's h-index: its insensitivity to the size of the most-cited papers. Where the h-index caps the credit any single paper can earn at h, the g-index lets exceptionally cited articles raise an author's score. It is defined as the largest number g such that the g most-cited papers together accumulate at least g-squared citations. Because it rests on cumulative rather than per-paper citation counts, the g-index always equals or exceeds the h-index and rewards researchers whose impact is concentrated in a few landmark works as well as those with broad, steady output.	The hg-index, proposed by Alonso, Cabrerizo, Herrera-Viedma, and Herrera in 2010, fuses the two best-known author metrics into a single composite. The h-index is robust but ignores how heavily an author's top papers are cited, while Egghe's g-index rewards those highly cited papers but can be swayed by a single outlier. The hg-index takes the geometric mean of the two, producing a value that lies between them and inherits a balance of their strengths: it remains close to the stable h-index while still responding to the citation impact captured by g. The authors showed that the geometric mean stays nearer to the smaller, more conservative h-index than the larger g-index, tempering the latter's sensitivity to extreme papers.