A sequential economic model of fertility behavior in developing countries.

Easterlin (1978) attempts to synthesize the demand side of the economic model, which is mostly applicable to developed countries, and the supply side. The synthesis assumes that fertility decision is made once and for all. This discussion is a sequential version of Easterlin's synthesis. It first considers the features of economic model, especially in its application to fertility analysis, and then presents the model in brief before examining the details. A woman's observed fertility is decomposed in the model into the "number of potential endowment of live-births" minus the "number of avoided live-births demanded." The number of potential endowment of live-births, referred to as "potential endowment" is defined as the number of live-births a woman has already had plus the number she would have in the remainder of her reproductive years if she and her husband never practiced deliberate contraception; the number of avoided-live-births demanded is defined as the number of live-births from a woman's potential endowment that is treated as a function both of the price of an avoided-birth and of excess endowment. This decomposition can be used to develop a theorectical framework that provides insights into the channels through which a particular variable affects observed fertility. The resulting framework, an extension of Easterlin's "synthesis model," can enhance knowledge of the determinants of fertility. It also increases the ability to make policy recommendations concerning population size and control. The broad theoretical framework is illustrated graphically. Some interesting theoretical implications of the theoretical framework include: higher fertility is consistent with a wider practice of deliberate contraception if potential endowment (E) rises more than the practice of deliberate contraception (z); and a positive relation between such variables as wife's education and fertility is possible.