Population Research and Policy Review 16: 561–578, 1997.
1997 Kluwer Academic Publishers. Printed in the Netherlands.
Cheaper by the dozen?
The marginal time costs of children in the Philippines
& JILL TIEFENTHALER
Abstract. The important relationship between fertility rates and economic development has
prompted many researchers to try and better understand the determinants of family size. It has
repeatedly been shown that the costs of children, both direct and indirect, are one of the most
important determinants of fertility, exerting a signiﬁcantly negative effect on birth rates in both
developed and developing countries. Many studies which investigate the relationship between
the costs of children and family size have assumed that these costs do not vary with parity.
However, there is substantial evidence that the marginal costs of children are not constant but
decrease with birth order in developed countries. In this paper, the hypothesis that there are
diminishing marginal time costs of children is tested using household data from the developing
country setting of the Philippines. By examining the determinants of additional time spent in
childcare before and after the birth of a child, it is found that the marginal time costs are not the
same across households of various sizes. Firstborn children cost signiﬁcantly more in terms
of additional mother’s time than children of higher birth orders. In addition, the time costs of
the second child are found to be signiﬁcantly greater than those of the third child. However,
these economies of scale in childcare are limited and do not extend beyond three children. The
effect of birth spacing on the marginal time costs of children is also found to be signiﬁcant.
Key words: Costs of children, Time allocation, Philippines
Both theoretical and empirical analyses of fertility behavior rely heavily on
the cost of children as a major determinant of family size (see, for example,
Becker 1960; Becker & Lewis 1973; Ben-Porath 1973; Borg 1989). The
cost of child rearing includes not only the direct expenditures on goods and
services, but also includes the opportunity cost or the value of parental time
foregone due to child rearing duties. Empirical studies show that proxies for
the direct price of children such as urban residence, child subsidies, and health
care costs vary inversely with family size (see DeTray 1973; Leibowitz 1990;
Whittington 1992) . Similarly, studies that include proxies for the opportunity
cost of children such as mother’s education and mother’s wage, indicate that
the price and quantity of children move in opposite directions (see Ben-Porath
1973; DeTray 1973).