Every year,
BioMed Central calculates unofficial impact factors for journals that have
published a significant number of research articles but do not yet have an
official impact factor. These unofficial impact factors use the same citation
data and methodology used by Thomson Scientific’s official impact factor
calculations.

Newly calculated
unofficial 2006 impact factors show a significantly increased citation rate for
BioMed Central journals. For example, BMC Biology and BMC Medicine, the flagship journals of the BMC
series, both increased their unofficial impact factors significantly. The 2006
unofficial impact factor for BMC
Biology is 4.43 (up from 3.81 in 2005) while for BMC
Medicine the 2006 figure is 4.17 (up from 2.52 in 2005).

Updated unofficial impact factors for more than 50 journals published by
BioMed Central are listed on our Impact Factor FAQ
page, alongside details of
official impact factors for a further 26 journals.

Overall, the
average unofficial impact factor for a BioMed Central journal increased by 0.39
compared to 2005. Other BioMed Central journals with impressive unofficial 2006
impact factors include Journal of
Neuroinflammation (4.36), Retrovirology (4.32), Cardiovascular Diabetology (4.00), Molecular
Cancer (3.62) and Journal of
Translational Medicine (3.30). Updated official 2006 impact
factors will be released by Thomson Scientific in June.