手法を比較

	Field-Normalized Citation Impact (MNCS)	Contemporary h-Index
分野	計量書誌学	計量書誌学
系統	Process / pipeline	Process / pipeline
提唱年	2011	2007
提唱者	Ludo Waltman, Nees Jan van Eck & colleagues (CWTS Leiden)	Antonis Sidiropoulos, Dimitrios Katsaros & Yannis Manolopoulos
種類	Field-normalized citation impact indicator	Age-discounted author impact index
原典	Waltman, L., van Eck, N. J., van Leeuwen, T. N., Visser, M. S., & van Raan, A. F. J. (2011). Towards a new crown indicator: Some theoretical considerations. Journal of Informetrics, 5(1), 37-47.	Sidiropoulos, A., Katsaros, D., & Manolopoulos, Y. (2007). Generalized Hirsch h-index for disclosing latent facts in citation networks. Scientometrics, 72(2), 253-280.
別名	Mean Normalized Citation Score, MNCS, normalized citation impact, new crown indicator	hc-index, time-weighted h-index, age-decayed h-index
関連	3	3
概要	The Mean Normalized Citation Score (MNCS) is the field-normalized citation impact indicator developed at the Centre for Science and Technology Studies (CWTS) in Leiden and articulated in Waltman and colleagues' 2011 paper on a new crown indicator. Raw citation counts cannot be compared across fields, because a molecular biology paper and a mathematics paper accumulate citations at vastly different rates, and older papers have had more time to be cited. The MNCS removes these distortions by dividing each paper's citations by the average citations of comparable papers in the same field, document type, and publication year, then averaging these normalized ratios. A value of 1 means performance exactly at the world average for the relevant fields, while values above or below 1 indicate above- or below-average impact.	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.