So sánh phương pháp

	m-Quotient (Hirsch m)	Contemporary h-Index	hg-Index (Composite Hirsch-Egghe)
Lĩnh vực	Trắc lượng thư mục	Trắc lượng thư mục	Trắc lượng thư mục
Họ	Process / pipeline	Process / pipeline	Process / pipeline
Năm ra đời	2005	2007	2010
Người khởi xướng	Jorge E. Hirsch	Antonis Sidiropoulos, Dimitrios Katsaros & Yannis Manolopoulos	Sergio Alonso, Francisco J. Cabrerizo, Enrique Herrera-Viedma & Francisco Herrera
Loại	Career-length-normalized author impact rate	Age-discounted author impact index	Composite author impact index
Công trình gốc	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.	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.
Tên gọi khác	Hirsch m-quotient, m-parameter, h-index per year	hc-index, time-weighted h-index, age-decayed h-index	Alonso hg-index, hg index, composite h-g index
Liên quan	3	3	3
Tóm tắt	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 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.