This chart shows the 2-Year Impact (comm only) of BMC Pregnancy and Childbirth over time and its percentile among journals. Only communications are counted in both the numerator (citations) and denominator (citable items).
How is the 2-year communication impact calculated?
The 2-year communication impact for year X equals the citations received in year X to communications published in years X-1 and X-2, divided by the number of communications published in those two years. Unlike the standard 2-year impact, only items classified as communications are counted in both the numerator and denominator.
