The EigenfactorTM algorithm ranks journals much as Google
ranks websites.
Scholarly references join journals
together in a vast network of
citations. The Eigenfactor algorithm uses the structure of the entire network
(instead of purely local citation information) to evaluate
the importance of each journal.
EigenfactorTM measures journal price as well as citation influence.
In collaboration with journalprices.com, Eigenfactor provides
information about price and value for thousands of scholarly
periodicals. While the Eigenfactor and Article Influence scores do not incorporate price information directly, the Cost-Effectiveness Search orders journals by a measure of the value per dollar that they provide.
EigenfactorTM contains 115,000 reference items.
Eigenfactor not only ranks scholarly journals
in the natural and
social sciences, but also lists newsprint, PhD theses, popular
magazines and more. In so doing, it more fairly values those journals bridging the gap between the social and natural sciences.
The EigenfactorTM algorithm adjusts for citation differences across disciplines.
Different disciplines have different standards
for citation and
different time scales on which citations occur. The average
article in
a leading cell biology journal might receive 10-30 citations
within two
years; the average article in leading mathematics journal would
do
very well to receive 2 citations over the same period. By using
the
whole citation network, the Eigenfactor algorithm automatically accounts
for these
differences and allows better comparison across research areas.
The EigenfactorTM algorithm uses 5-year citation data.
In many research areas, articles are not frequently cited
until several years after publication. Therefore, measures
that only look at
citations in the first two years after publication can be be
misleading. The Eigenfactor score is calculated based on the citations
received
over a five year period.
The EigenfactorTM scores are completely free and completely searchable.