Henk Moed at the Centre for Science and Technology
Studies (CWTS) at Leiden University has recently developed
a new journal indicator, the Source Normalized Impact per Paper (SNIP), based
on citation data from Scopus. A journal’s
SNIP can be thought of as similar to a normalized Impact Factor, which weights citations to adjust
for the fact that some fields are more citation-rich than others. The intention
is that SNIPs will allow more effective comparison of journals between
different fields.  More
information about SNIPs and how they are calculated can be found  in Moed’s recent article
and at www.journalindicators.com.

Orphanet Journal of Rare Diseases is BioMed Central’s highest-ranking journal based
on the SNIP metric, with a value of 1.31 (the median SNIP for the ~17,000
journals in Scopus is 0.52). This places the journal in the top 4% of all
journals listed in Scopus. For comparison, the journal’s Impact Factor
of 3.14 makes it the 22nd most highly-rated BioMed Central journal by Impact
Factor. The contrast between these two rankings demonstrates that caution is
needed when interpreting citation metrics, as much depends on the algorithm
used. The SNIP provides a valuable new means to identify high quality journals in
fields which may not in general be highly cited. 

Other BioMed Central
journals which are ranked particularly highly by the SNIP metric include: