New Letter to the Editor

Bornmann, Lutz lutz.bornmann at GV.MPG.DE
Sun Mar 29 11:12:29 EDT 2015

Dear Loet,

Many thanks for your feedback. The most important thing is to use a time- and field-normalized impact indicator in order to produce such a list. The used method of normalization is another issue.

I agree we (L.& L.) argue for percentiles and against the use of WoS subject categories for building reference sets. However, I claim that the standard in bibliometrics is (still) the MNCS based on WoS subject categories.

In my opinion, the standard indicator in a field is defined by its frequency of professional use (and not by advantages and disadvantages of relevant indicators). In other words, if professional bibliometricians (and not amateur-bibliometricians) mostly use the MNCS (based on WoS subject categories), this is the standard then.



From: ASIS&T Special Interest Group on Metrics [mailto:SIGMETRICS at LISTSERV.UTK.EDU] On Behalf Of Loet Leydesdorff
Sent: Sunday, March 29, 2015 4:17 PM
Subject: Re: [SIGMETRICS] New Letter to the Editor

Adminstrative info for SIGMETRICS (for example unsubscribe):
Dear Lutz,

This letter is remarkable because you plead for using the Mean Normalized Citation Score MNCS. But:

1.       Why should one use the mean of a highly skewed distribution? In other papers, you argued in favour of using percentile rank classes. At least, one could use the top-10% or the median as a non-parametric alternative.

2.       It is far from clear how one should normalize. Normalization presumes reference sets. One often use Web-of-Science Subject Categories for this, but these have been shown to be sometimes very heterogeneous, and in other cases overlapping. I would not advise to use them for evaluation purposes because one may end up with a lot of error.

The Leiden Rankings 2014 are for these reasons (among others) no longer based on MNCS (as they were in 2013). You argue that these are de-facto standards, but why should one continue to use de-facto standards that are not valid?



Bornmann, L., & Mutz, R. (2011). Further steps towards an ideal method of measuring citation performance: The avoidance of citation (ratio) averages in field-normalization. Journal of Informetrics, 5(1), 228-230.

Loet Leydesdorff and Lutz Bornmann, The Operationalization of "Fields" as WoS Subject Categories (WCs) in Evaluative Bibliometrics: The cases of "Library and Information Science" and "Science & Technology Studies"<>, Journal of the Association for Information Science and Technology (in press); doi: 10.1002/asi.23408<>

Loet Leydesdorff
Emeritus University of Amsterdam
Amsterdam School of Communications Research (ASCoR)
loet at <mailto:loet at> ;
Honorary Professor, SPRU, <> University of Sussex;
Guest Professor Zhejiang Univ.<>, Hangzhou; Visiting Professor, ISTIC, <> Beijing;
Visiting Professor, Birkbeck<>, University of London;

From: ASIS&T Special Interest Group on Metrics [mailto:SIGMETRICS at LISTSERV.UTK.EDU] On Behalf Of Bornmann, Lutz
Sent: Sunday, March 29, 2015 3:22 PM
Subject: [SIGMETRICS] New Letter to the Editor

Bornmann, L. (in press). Nature’s top 100 revisited. Journal of the Association for Information Science and Technology

Recently, Van Noorden, Maher, and Nuzzo (2014) published a list of papers which are among the 100 most highly cited papers of all time. This letter argues that such a list should not be produced on the base of bare citation counts, but normalized bibliometric indicators – the standard in bibliometrics.


Dr. Dr. habil. Lutz Bornmann
Division for Science and Innovation Studies
Administrative Headquarters of the Max Planck Society
Hofgartenstr. 8
80539 Munich
Tel.: +49 89 2108 1265
Mobil: +49 170 9183667
Email: bornmann at<mailto:bornmann at>

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