Back in September
Potter, R.G. 1971. "Births Averted by Induced Abortion: An Application of Renewal Theory." Theoretical Population Biology, 3, no. 1 (1972): 69-86.
An analytical model that yields estimates of births averted by 1 segment of contraception (i.e., period of usage of a method between its initiation and its next interruption owing to accidental pregnancy, switch to another method, or stopping contraception) as a function of family planning services is presented. The model, which does not include such factors as sterility, mortality, or age-related changes in fecundity, is realistic only for the first half of the childbearing period. Derivation and analyses of the model are presented. It is suggested that this model is best fitted within the context of young, "normally fecund" IUD and oral contraception acceptors in a mass family planning program setting.