Search

IN A justly famous article, Verdoorn (1949) examined the relations between changes in labour productivity and growth in industrial output for a number of countries prior to World War II. Using national data on growth in employment and output for fifteen countries in the interwar period and separately for individual sectors from four countries, Verdoorn found a sizeable positive relation between the rate of growth of labour productivity and the rate of growth of output. Investigations of more recent data have generally reported similar results.2 Consequently, this empirical relation has become known as Verdoorn's Law. In explanation of his findings, Verdoorn (1949) notes that "one would have expected a priori to find a correlation between labour productivity and output, given that the division of labour only comes about through increases in the volume of production; therefore the expansion of production creates the possibility of further rationalization which has the same effect as mechanisation."' Clark (1967, pp. 260-266) and Vaciago (1975) argue that Verdoorn's findings provide evidence for the existence of increasing returns to scale in the manufacturing sector. Salter (1966, pp. 144-146) and Thirlwall (1980) suggest that Verdoorn's results are explained by economies of scale, by a positive causal association between output growth and the pace of technological progress, and by capital deepening in sectors ex

This article develops a model of mortality that shows how biological, demographic, and environmental factors interact to affect an individual's probability of dying. To illustrate the usefulness of the model, we derive from it (as special cases) the Brass system of model life tables and the proportional-hazard mortality model and apply a logit version of the model to analyze the determinants of child mortality in Sri Lanka.

This paper proposes a new procedure for estimating the level and timing of fertility control within marriage as well as the social and economic correlates of these reproductive parameters. The method precludes the need for data such as trends in birth intervals and age at last birth and other data that is often not available. The method does require data on children ever born, age at marriage, and the socioeconomic characteristics of couples, information often gathered in censuses and surveys. Some assumptions of the model are: in the absence of deliberate fertility control, a woman can reproduce at each age according to a natural fertility schedule. A couple can choose the date after marriage at which control begins, and the level at which it is controlled. Application of this procedure to samples of US women aged 45-54 from the 1965 National Fertility Survey and women aged 20-44 from the 1970 National Fertility Survey yielded results that were consistent with analyses of special surveys on contraceptive use. In particular, for the sample of older women, it was estimated that the control of fertility began relatively soon after marriage, with control beginning at later durations for younger women, and that the extent of control was quite high, with the average level of control of non-Catholics exceeding that of Catholics. The evidence of early control is consistent with other research; specifically, the 1960 Growth of American Families Study. For the sample of younger women, it was estimated that the duration of marriage after which control began was longer for older women and for Catholics, but that the extent of fertility control, once it began, did not differ by religion.

The impact of children on household economic activity is estimated for 573 farm and nonfarm rural households in Laguna Province, the Philippines. Time allocation estimates of average hours worked per week in the year preceding the survey data and income estimates are based on interview responses of mothers and fathers. In farm families, fathers contributed about 65% of work time, mothers about 20%, and children 15%, and the contributions to total family income approximate these percentages. Children contribute about 30% of the family time used for nonincome home production and 25% of that for childcare. Nonfarm fathers spend about 7 hours less per week in income-earning activities than farm fathers. The presence of children has a significant influence on parents' allocation of time. Children of all ages stimulate fathers to work more hours, while young children reduce mothers' time in income-earning activities and leisure. Older sons substitute for mothers' work time while older daughters substitute for mothers' home-production time; their presence raises the number of hours mothers spend in income-earning activities. Older children of both sexes increase mothers' leisure time substantially.

"This paper presents an explicit derivation of effects of age misstatement on census survival rates (CSR) and life table survival rate (LTSR) estimates of net migration and net migration rates. In the presence of age misstatement, CSR estimates of migration and migration rates are generally biased, although the direction of bias is not always clear. The paper also shows how the analysis of errors due to age misstatement is related to past analyses of errors due to underenumeration."