The A&A Experience With Impact Factors
ABSTRACT There is a widespread impression that the scientific journal "Astronomy & Astrophysics" (A&A) has a smaller impact, as measured by citations to articles, than some of the other major astronomy journals. This impression was apparently supported - and probably created - by the Journal Citation Report (JCR), which is prepared annually by the Institute of Scientific Information (ISI) Web of Knowledge. The published poor impact factor of A&A was in fact wrong and was due to a serious flaw in the method used by ISI Web of Knowledge to determine it. The resulting damage inflicted upon A&A by the JCR is incalculable.
arXiv:astro-ph/0403184v1 8 Mar 2004
THE A&A EXPERIENCE WITH IMPACT FACTORS
SCFAB-AlbaNova, SE-106 91 Stockholm, Sweden
There is a widespread impression that the scientific journal Astronomy &
Astrophysics (A&A) has a smaller impact, as measured by citations to ar-
ticles, than some of the other major astronomy journals. This impression is
apparently supported and probably created by the Journal Citation Report
(JCR), which is prepared annually by the Institute of Scientific Information
(ISI) Web of Knowledge. In the JCR statistics, A&A has over a number of
years shown a considerably lower impact factor than some of the other main
journals in the field. For example, Abt (2003) presented a table in last year’s
volume of this series (Organizations and Strategies of Astronomy - Vol. 4)
in which A&A was in 15th place (behind such journals as ”Acta Astron.”
and ”Astrophys. Lett. & Comm.”). The published poor impact factor of
A&A is in fact due to a serious flaw in the method used by ISI Web of
Knowledge to determine it. The resulting damage inflicted upon A&A by
the JCR is incalculable. Attempts to correct the wrong impression are now
proceeding (Sandqvist 2003, Heck 2003).
2. JCR’s Erroneous Method and Its Correction
Owing to the short abbreviation (A&A) with which articles in Astronomy
& Astrophysics are usually cited, and the possible non-uniqueness of this
abbreviation among the scientific journals covered by the JCR, these were
not counted. Instead, such old abbreviations as ”Astron. Astrophys.” were
used by JCR. Anyone active in the astronomical literature will realize the
catastrophic effect of this choice. As noted by Abt (2003), a smilar situ-
ation occurred with The Astrophysical Journal, for which the three-letter
abbreviation (ApJ) had been considered too challenging. After account-
ing for citations with ApJ, the impact factor of The Astrophysical Journal
increased by more than a factor of two from 2000 to 2001.
As chairman of the A&A Board of Directors, I contacted the ISI Web of
Knowledge in the fall of 2002, as soon as we had discovered the erroneous
abbreviation that JCR was using for A&A. After some hesitation, the ISI
Web of Knowledge decided to change its routines, and in the future the
abbreviation A&A would be taken into account. In-house studies at the ISI
Web of Knowledge showed that very little confusion arose through this, and
more importantly, after accounting for these citations, the impact factor of
A&A became comparable to that of the other major astronomy journals
and the total number of citations second only to The Astrophysical Journal.
Apologizing, the ISI informed me in the fall of 2003 that it had made a
reconstruction of what A&A’s impact factor would have been in the year
2000, if the proper Journal abbreviation had been used. The result was
heartening for A&A: the A&A impact factor had rebounded from a wrong
value of 2.79 to a corrected value of 4.352 with a resulting change of rank
from a wrong value of 11th to a corrected value of 4th out of 37 in the
category of Astronomy and Astrophysics!
Since the impact factor is defined as the number of papers cited for
a given journal divided by the total number of papers published in that
journal, averaged over the past two years, the true positive effect of this
correction for A&A will be slower than desired.
3. Confidence in ISI?
How trustworthy are the citation statistics published by JCR? Given that
ISI is a commercial enterprise, expensive, and that evaluations of individ-
uals, institutes and scientific disciplines are based on their data, their con-
sumers have a right to expect absolute professionalism. We have seen one
example of gross failure in the previous section. Another example (which,
however, does not involve A&A directly) is detailed below.
On ISI, a January 2004 search for citations of SCHNEIDER P in 2001
2 Schneider P. PHYS REP 340 292 2001
where ”2” is the total number of citations.
A similar search on the NASA Astrophysics Data System (ADS) yielded:
2001 PhR 340 ...291B 113.000 01/2001 Bartelmann, M.; Schneider, P.
Weak gravitational lensing
where ”113” is the total number of citations.
This huge difference in the total number of citations reported by the
ISI and ADS is due to an error in the ISI data base which claimed the first
page number of the article to be ”292”, whereas its correct value should
THE A&A EXPERIENCE WITH IMPACT FACTORS
be ”291” as properly stated by ADS. A search using the name of the first
author (Bartelmann) did give the correct number of citations for this article
at both ISI and ADS, but this does not help Dr. Schneider, though. When
informed of this error, the ISI responded that a correction could take ”up
to 4 weeks”. This reply does not show the level of professionalism that one
would expect from a company which has taken a large influence in shaping
the careers of scientists. Whether the astronomical funding agencies should
continue to rely heavily upon ISI when other citation tools have become
available now appears questionable.
4. Damage Inflicted Upon A&A
Although the A&A Board of Directors is gratified by the new development
in the JCR with respect to A&A, we are extremely concerned about the
damage inflicted upon our Journal by ISI, in particular since it also has
had detrimental personal and institutional consequences for A&A’s authors.
Also serious is the fact that it will take some time before the full impact
of this change in the ISI software will have been made, so that it correctly
reflects the proper citation index and impact factor for our Journal. And
how long will it take before the Astronomical Community has been made
fully aware of the JCR error and its correction, not to mention the difficulty
of reaching financing agencies which make ample use of journal impact
Problems that have come to our attention vary in different countries:
(1) Some libraries are considering cancelling subscriptions to A&A since
they only want the astronomical journals with the ten highest impact fac-
tors. The erroneous published value of 15th place for A&A would thus
disqualify it for these libraries’ acquisition lists.
(2) Some ministries naturally turn to impact factors when making com-
parative studies between scientific disciplines and their general impact, with
the purpose of drawing up priority lists for future large-scale financing. Such
studies, making use of the erroneous published values, will have had very
serious effects upon the efforts of some A&A authors to achieve future
(3) Some institutes do not select A&A papers in their top ten list in their
annual reports due to the erroneous published value of the A&A impact
(4) Some astronomers use the low erroneous published value for the
A&A impact factor as a reason for not publishing in A&A which, of course,
is highly detrimental to our Journal.
The damage to A&A has been done. The error has been found. The error
has been corrected by ISI. This information must now be disseminated
throughout the Astronomical Community, the Institutional Libraries, the
Financing Agencies, the General Society of Impact Factor Consumers. This
short communication is one such attempt. The A&A Board of Directors is
grateful if you, the reader, will do the same.
Abt, H.A. (2003) The Institute for Scientific Information and the Science
Citation Index, in Organizations and Strategies in Astronomy - Vol. 4, Ed.
A. Heck, Kluwer Academic Publishers, Dordrecht, pp. 197-204
Heck, A. (2003) WRONG IMPACT!, European Astronomical Society Newslet-
ter, Issue 26, December 2003, pp. 4-5
Sandqvist, Aa. (2003) Remark on Impact Factor, A&A, Vol. no. 402,
To be published in “Organizations and Strategies in Astronomy – Vol.
5”, Ed. A. Heck, Kluwer Academic Publishers, Dordrecht (2004)