An extreme case: a single paper caused sudden inflation of a journal impact factor

The journal impact factors for 2009 have been announced from Thomson Reuters. Jordan Dimitrov and his colleagues has reported in Nature about a case of a sudden inflation of a journal impact factor. The impact factor of the journal Acta Crystallographica A, which has not exceeded 2.385 for the past four years, was 49.926, which comes to the second highest among all journals! This dramatic increase in impact factor is very likely to be attributed to a single paper, which was cited 5624 times. By contrast, all the other papers of this journal (71 papers), published in the same year, was cited only 342 times.
It would be nonsense to believe in impact factors and now we should be aware of the difference between symbols and real things (Lutus, 2001).

Impact factor trends of Acta Crystallographica A.

• 2005: 1.791
• 2006: 1.676
• 2007: 2.385
• 2008: 2.051
• 2009: 49.926

References

• Dimitrov JD, Kaveri SV, Bayry J (2010) Metrics: journal's impact factor skewed by a single paper. Nature 466: 179.
• Lutus P (2001) How we confuse symbols and things. URL: http://www.arachnoid.com/lutusp/symbols.html