Normalized Impact Factor (NIF) Re: [SIGMETRICS] Abs&Comment, Sen, Symbols and formulas for a few bibliometric concepts Re: [SIGMETRICS] ABS: Solari, A new approach to the SCI Journal Citation Reports, a system for evaluating scientific journals

Johannes Stegmann stegmann at UKBF.FU-BERLIN.DE
Thu Jun 8 09:27:03 EDT 2000

There is still another recent article in Scientometrics dealing with
(subfield specific) impact factor (re-) normalization:
Ramirez, A.M., Garcia, E.O., Del Rio, J.A. Renormalized impact factor.
Scientometrics 47 (1), 3-9 (January 2000).
The "renormalized impact factor is calculated using the highest impact
factor in the category (same as in the article by Sen) and the median value
of the impact factors of the journals constituting the category.

The formula given in the article by Ramirez et al. is:

   Fc = (F - Fmed) / (Fmax - Fmed)

Fc = category-dependent impact factor,
F = impact factor (of the journal in question)
Fmed = median (of the category's impact factors)
Fmax = highest impact factor in the category

For journals listed in more than one category, Ramirez et al. calculate the
"renormalized impact factor Fr" as the mean value of the two or more Fc's.
Fr is identical with Fc for journals listed only in one category.

I wonder a bit that the "Normalized Mean Citation Rate" (NMCR) proposed by
Glaenzel 10 years ago (as far as I know) isn't like a kind of "standard" in
crossfield comparisons. The NMCR is (as I understand it) the ratio of a
journals' impact factor and the subfield's impact factor, i.e. the impact
factor of the journal divided by the impact factor of the subfield. The
subfield impact factor may be the average of the impact factors of the
journals constituting the subfield (unweighted average) or - better - the
ratio of cites given to all journals in the subfield divided by the papers
("citable items) published in the subfield's journals.
This ratio - NMCR - immediately shows if a journal is above or below the
standard in its field, and it is calculated in the same way as the
individual journal's impact factor (taking the weighted average of the
subfield). All data can be retrieved from the JCR (on CDROM), too.

Johannes Stegmann

Dr. Johannes Stegmann      Univ. Hospital Benjamin Franklin
Free University Berlin     Medical Library
stegmann at Hindenburgdamm 30
Tel.: +49 30 8445 2035     D-12200 Berlin
Fax:  +49 30 8445 4454     Germany

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