51 academic journals were excluded from Thomson Reuters'
research impact factor ranking
2011. On annual basis, journals that attempt to significantly climb
ranks through self-citation are banned for a couple of years. This
year, 28 new offenders were subject to this measure. In 2007, this
was only the case for 9 journals.
By comparison, this number is still relatively small given that
Thomson Reuters includes more than 10,500 periodicals in its
ranking. However, one case of systematic manipulation stands out.
Three months ago Scholarly Kitchen
revealed that The Scientific World Journal, Cell
Transplantation and Medical Science Monitor had used mutual
citations to artificially boost their research impact standing.
Defining whether "anomalous citation patterns" are in fact
questionable for the science community is difficult, as a recent
blog by Nature magazine argues. Thomson Reuters itself only
investigates cases where self-citation leads to significant boosts
of the impact factor.