ABS: Jacso, Number Game

Gretchen Whitney gwhitney at UTK.EDU
Wed Feb 21 16:28:44 EST 2001

Author e-mail: peterjacso at yahoo.com

Peter Jacso, University of Hawaii
"Savvy Searching: the Number Game"
Online Information Review, 24(2), 2000, 180-183

Article, in PDF Format:

If you do not have the Adobe reader for .pdf documents, please visit

Supplemental material:

The editorial illustrates the possible consequences of the policy in
determining the denominator (the "citable" items in a journal), and of the
errors in assigning document tyes to publications when calculating the
impact factor of journals.

The 1998 edition of Social Sciences Journal Citation Reports (JCR) -
released in Fall 1999 - ranks _Contemporary Psychology as the journal with
the highest impact factor among the nearly 500 psychology and psychiatry
journals, and ranks it second among all the social science journals
monitored by the Institute for Scientific Information (ISI).  According to
JCR, _Contemporary Psychology_ received 30 citations in 1996 and 1997, and
had a total of 3 items considered "citable articles" published in the same
period, yielding an impact factor of 10.

For calculating the impact factor, ISI counts only original research
articles, notes, and literature review articles in determining the
denominator.  This is arguable as book reviews, database reviews, letters
to the editor are indeed cited. When book reviews, database reviews do get
cited, the impact factor may increase significantly.

The 1998 Social Sciences JCR produced an extreme ranking for an additional
reason. The three items are clearly book reviews, but they were assigned
the wrong document type (DT=ARTICLE) by ISI, thus qualifying for "citable

The irony is that this journal should not have been included at all in the
stable of journals monitored by ISI as it is a journal of book reviews and
does not have publications that would qualify it for coverage in JCR.  The
JCR policy of not counting certain document types when determining the
denominator may unduly increase the impact factor of journals that do
receive citations to those types of documents.  The error in document type
identification triggered an extremely high ranking in the example
described.  In the case of other journals - with correct and consistent
document type assignment - the distortion in ranking may be far more
subtle and far less likely to be spotted.

Gretchen Whitney, PhD                                     tel 865.974.7919
School of Information Sciences                            fax 865.974.4967
University of Tennessee, Knoxville TN 37996 USA           gwhitney at utk.edu

More information about the SIGMETRICS mailing list