Abstract :
In this paper we investigate the scattering of journals and
literature obsolescence reflected in more than 137,000
document delivery requests submitted to a national document
delivery service.W e first summarize the major
findings of the study with regards to the performance of
the service.W e then identify the “core” journals from
which article requests were satisfied and address the following
research questions: (a) Does the distribution of
(core) journals conform to the Bradford’s Law of Scattering?
(b) Is there a relationship between usage of journals
and impact factors, journals with high impact factors
being used more often than the rest? (c) Is there a relationship
between usage of journals and total citation
counts, journals with high total citation counts being
used more often than the rest? (d) What is the median age
of use (half-life) of requested articles in general? (e) Do
requested articles that appear in core journals get obsolete
more slowly? (f) Is there a relationship between obsolescence
and journal impact factors, journals with
high impact factors being obsolete more slowly? (g) Is
there a relationship between obsolescence and total citation
counts, journals with high total citation counts being
obsolete more slowly? Based on the analysis of findings,
we found that the distribution of highly and moderately
used journal titles conform to Bradford’s Law.The median
age of use was 8 years for all requested articles.
Ninety percent of the articles requested were 21 years of
age or younger.Articles that appeared in 168 core journal
titles seem to get obsolete slightly more slowly than
those of all titles.W e observed no statistically significant
correlations between the frequency of journal use and ISI
journal impact factors, and between the frequency of
journal use and ISI- (Institute for Scientific Information,
Philadelphia, PA) cited half-lives for the most heavily
used 168 core journal titles.There was a weak correlation
between usage of journals and ISI-reported total citation
counts.No statistically significant relationship was
found between median age of use and journal impact factors
and between median age of use and total citation
counts.There was a weak negative correlation between
ISI journal impact factors and cited half-lives of 168 core
journals, and a weak correlation between ISI citation halflives
and use half-lives of core journals.No correlation
was found between cited half-lives of 168 core journals
and their corresponding total citation counts as reported
by ISI.Findings of the current study are discussed along
with those of other studies.
