An Economic Analysis of Fertility

THE inability of demographers to predict western birth rates accurately in the postwar period has had a salutary influence on demographic research. Most predictions had been based either on simple extrapolations of past trends or on extrapolations that adjusted for changes in the agesex-marital composition of the population. Socio-economic considerations are entirely absent from the former and are primitive and largely implicit in the latter. As long as even crude extrapolations continued to give fairly reliable predictions, as they did during the previous half century, there was little call for complicated analyses of the interrelation between socio-economic variables and fertility. However, the sharp decline in birth rates during the thirties coupled with the sharp rise in rates during the postwar period swept away confidence in the view that future rates could be predicted from a secularly declining function of population compositions. Maithus could with some justification assume that fertility was determined primarily by two primitive variables, age at marriage and the frequency of coition during marriage. The development and spread of knowledge about contraceptives during the last century greatly widened the scope of family size decision-making, and contemporary researchers have been forced to pay greater attention to decision-making than either Maithus or the forecasters did. Psychologists have tried to place these decisions within a framework suggested by psychological theory; sociologists have tried one suggested by sociological theory, but most persons would admit that neither framework has been particularly successful in organizing the information on fertility. Two considerations encouraged me to analyze family size decisions within an economic framework. The first is that Maithus' famous discussion was built upon a strongly economic framework; mine can be viewed as a generalization and development of his. Second, although no