| Chapter 2: | Background and Theoretical Development |
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fertility. For example, Bongaarts (1978) refined the intermediate-variable framework by reducing the number of determinants. The 11 intermediate variables developed by Davis and Blake (1956) had proved difficult and led to complex fertility models. To overcome this, Bongaarts (1982) suggested that variation in human fertility can be accounted for by five proximate determinants of fertility instead of intermediate variables, thus arguing that differences in fertility from one population to the other are largely accounted for by only four of those variables: (a) proportion of the population that is married, (b) use of contraceptives, (c) incidence of abortion, and (d) involuntary infecundity. By introducing proximate determinants of fertility Bongaarts argued that if all women remain married throughout their reproductive period, had no induced abortion, experienced no lactational infecundity, and used no contraception, then they would achieve their maximum fertility level (which is approximately 15.3 children). Thus, the only way to have fertility levels below the maximum capacity, according to Bongaarts, depends on the extent of lactational infecundity, induced abortion, and contraceptive use and through delayed marriage, marital disruption, or long-term spousal separation (Moreno, 1991). Bongaarts thus introduced four factors that influence the reduction of fertility: (a) index of nonmarriage (Cm), (b) index of contraception (Cc), (c) index of lactational infecundity (Ci), and (d) index of induced abortion (Ca). Thus, the observed total fertility (TF) of a population, according to Bongaarts, is the product of all these:
A substantial number of demographic studies have used the proximate-determinants framework to understand the changes