# [Sigmetrics] Global and average Impact Factors

Loet Leydesdorff loet at leydesdorff.net
Tue Oct 24 04:00:53 EDT 2017

```Dear Isidro:

>- "Global Impact Factor"= the sum of all the IF of the papers they
>produced (without any normalization)
>- "Average Impact Factor" = the average of IF per paper (or per author)
>
1. I assume that you meant with "IF of the papers" the IFs of the
journals in which the papers were published. This is a first source of
error. The lack of normalization a second.

2. Please, explain why averaging these numbers would be "an horrendous
mathematical error". Perhaps, in terms of formulas? I can see that it is
not a very smart indicator. :-)

Best,
Loet

>
>This is not a part of debate about the IF, this is an horrendous
>mathematical error (I learned this is an error in primary school!).
>And we need a strong answer from ISSI and bibliometrics community.
>
>Best,
>
>El 23/10/2017 a las 10:53, Isidro F. Aguillo escribió:
>>Dear all,
>>
>>In spite of the large number of papers (and declarations) against the
>>misuse and abuse of the IF, this indicator still appears frequently in
>>the "bibliometric" sections of the reports of many academic and
>>research institutions. But to my surprise I just discovered that most
>>of Spanish health-related institutions, including several of the most
>>prestigious ones, are using derived indicators like Impact Factor
>>Global (adding all the IF values of the papers) or Average Impact
>>Factor (usually per paper, but also per author) that are gross
>>mathematical aberrations. The reason for making public these
>>"indicators" is because the funding agencies are asking for them,
>>including local and national govts, private foundations and ... EC
>>(!!??).
>>
>>I do not know if it is possible some action of ISSI or even from
>>Clarivate to stop the use of these pseudo-indicators.
>>
>>
>
>--
>**************************************************************
>Isidro F. Aguillo
>Dr. Honoris Causa Universitas Indonesia
>Dr. Honoris Causa National Research Nuclear University Moscow
>Editor Rankings Web
>Cybermetrics Lab - Scimago Group, IPP-CSIC
>
>isidro.aguillo at csic.es
>ORCID 0000-0001-8927-4873
>ResearcherID: A-7280-2008
>Scholar Citations SaCSbeoAAAAJ
>Rankings webometrics.info
>***************************************************************
>
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