This chart shows the 2-year impact factor of BMC Pregnancy and Childbirth excluding self-citations over time and its percentile among journals. Self-citations — citations from articles in the same journal — are removed from the numerator.
How is the 2-year impact (no self-citations) calculated?
The 2-year impact (no self-citations) for year X equals the citations received in year X to items published in years X-1 and X-2, divided by the number of citable items published in those two years. Self-citations — citations originating from articles published in the same journal — are excluded from the numerator.
