Lundberg, J (Lundberg, Jonas) Lifting the crown-citation z-score JOURNAL OF INFORMETRICS, 1 (2): 145-154 APR 2007

[Eugene Garfield]

E-mail Address: jonas.lundberg at ki.se 

Author(s): Lundberg, J (Lundberg, Jonas)
 
Title: Lifting the crown-citation z-score 

Source: JOURNAL OF INFORMETRICS, 1 (2): 145-154 APR 2007 

Language: English 

Document Type: Article 

Author Keywords: citation; indicator; normalization; research assessment; 
z-score 

Keywords Plus: SCIENCE; INDEX 

Abstract: Researchers worldwide are increasingly being assessed by the 
citation rates of their papers. These rates have potential impact on 
academic promotions and funding decisions. Currently there are several 
different ways that citation rates are being calculated, with the state of 
the art indicator being the crown indicator. This indicator has flaws and 
improvements could be considered. An item oriented field normalized 
citation score average ((c) over bar (f)) is an incremental improvement as 
it differs from the crown indicatorin so much as normalization takes place 
on the level of individual publication (or item) rather than on aggregated 
levels, and therefore assigns equal weight to each publication. The 
normalization on item level also makes it possible to calculate the second 
suggested indicator: total field normalized citation score (Sigma c(f)). A 
more radical improvement (or complement) is suggested in the item oriented 
field normalized logarithm-based citation z-score average ((c) over bar (fz
[ln]) or citation z-score). This indicator assigns equal weight to each 
included publication and takes the citation rate variability of different 
fields into account as well as the skewed distribution of citations over 
publications. Even though the citation z-score could be considered a 
considerable improvement it should not be used as a sole indicator of 
research performance. Instead it should be used as one of many indicators 
as input for informed peer review. (c) 2007 Elsevier Ltd. All rights 
reserved. 

Addresses: Karolinska Inst, Med Management Ctr, Dept Learning Informat 
Management & Eth, SE-17177 Stockholm, Sweden; Karolinska Inst, Strategy & 
Dev Off, SE-17177 Stockholm, Sweden 

Reprint Address: Lundberg, J, Karolinska Inst, Med Management Ctr, Dept 
Learning Informat Management & Eth, SE-17177 Stockholm, Sweden. 

Cited Reference Count: 13 

Times Cited: 2 

Publisher: ELSEVIER SCIENCE BV 

Publisher Address: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS 

ISSN: 1751-1577 

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