Bongaarts’ aggregate model of the proximate determinants of fertility
Bongaarts (1978, 1982) and Bongaarts and Potter (1983) refined Davis and Blake’s framework into 7 important factors, which were termed as the proximate determinants of fertility, to understand variations in level of fertility between populations.
The 7 proximate determinants are:
- proportion of married women among all women of reproductive age
- contraceptive use and effectiveness
- duration of postpartum infecundability (or postpartum insusceptibility)
- induced abortion
- fecundability (including frequency and timing of intercourse)
- prevalence of permanent sterility
- spontaneous intrauterine mortality
Out of the 7 proximate determinants of fertility, Bongaarts (1982) showed that 4 determinants are most important in terms of explaining variations in fertility levels of populations.
- proportions of women married or in sexual union (as proxy of % of women exposed to sexual intercourse)
- contraceptive use and effectiveness
- duration of postpartum infecundability (or postpartum insusceptibility)4
- induced abortion
These 4 proximate determinants are of most importance both because they differ greatly between populations and because fertility is highly sensitive to changes in them. In certain situations, one or more of the other proximate determinants may play an important role, e.g. high levels of primary and secondary sterility in parts of Africa. Also sexual activities are often not confined only within marriage. These limitations of Bongaarts’ model will be critically discussed in Section 9 and the revised model by John Stover (1998) will be introduced in Section 10.
4 Bongaarts modified the definition of postpartum infecundability to the combined effect of postpartum amenorrhea and abstinence (Bongaarts 1982).