Errors in the Impact Factors computed and published by the ISI?

[Juan Miguel Campanario]

Hello!
This is my first message

The impact factor of a given journal a given year (for example 2003) is 
computed as follows:

                     Citations in 2003 to documents published in 2002 and 2001
IF (2003) = 
---------------------------------------------------------------------------------
                     Citable items published in 2002 and 2001


             It seems to me that there are some errors in the numbers 
published by the ISI in the Web of Science. I have used the data stored in 
the Journal of Citation Report included in the version of Web of Science 
available for the universities in Spain. Table shows some errors that I 
have noticed. Please, could anyone tell me if I am doing something wrong or 
the errors are real?

Journal
ATHEROSCLEROSIS SUPPLEMENTS
Year 2003
Citations 112
Items 35
IF (ISI) 4.457
Citations/Items=3.200

CA-A CANCER JOURNAL FOR CLINICIANS
Year 2001
Citations 1078
Items 34
IF (ISI) 35.933
Citations/Items=31.706

Regards

Juan Miguel Campanario
(juan.campanario at uah.es)


Departamento de Física
Edificio de Ciencias,
Universidad de Alcalá,
28871 Alcalá de Henares,
Madrid (Spain)

-------------------------------------------------------------------
Juan Miguel Campanario (http://www.uah.es/otrosweb/jmc)

A solas mi vida paso, ni envidiado ni envidioso
------------------------------------------------------------------- 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.asis.org/pipermail/sigmetrics/attachments/20060301/ac1a6f0a/attachment.html>