Showing papers by "Duncan Thomas published in 1993"

The distribution of income and expenditure within the household

Abstract: Most economic models of the household assume that it may be treated as if all members share the same preferences or one member (a dictator) makes all resource allocation decisions. That assumption is tested by asking whether income in the hands of men has the same impact on household commodity demand as income in the hands of women. Drawing on budget data from Brazil, we find that the distribution of income among men and women within the household does affect demand patterns and this is true for both non-labor income as well as total income. Income in the hands of women, relative to men, is associated with a larger increase in the share of the household budget devoted to human capital (household services, health and education) and also leisure (recreation and ceremonies) goods. The proportion of the budget spent on food declines more if the income is in the hands of women although food composition also changes and nutrient intakes rise faster as women's income increases. When the sample is restricted to only those couples in which both have some income, however, there is little evidence that income in the hands of men and women have significantly different effects on commodity consumption.

Principles of study design in environmental epidemiology.

Abstract: This paper discusses the principles of study design and related methodologic issues in environmental epidemiology. Emphasis is given to studies aimed at evaluating causal hypotheses regarding exposures to suspected health hazards. Following background sections on the quantitative objectives and methods of population-based research, we present the major types of observational designs used in environmental epidemiology: first, the three basic designs involving the individual as the unit of analysis (i.e., cohort, cross-sectional, and case-control studies) and a brief discussion of genetic studies for assessing gene-environment interactions; second, various ecologic designs involving the group or region as the unit of analysis. Ecologic designs are given special emphasis in this paper because of our lack of resources or inability to accurately measure environmental exposures in large numbers of individuals. The paper concludes with a section highlighting current design issues in environmental epidemiology and several recommendations for future work.

Methodologic research needs in environmental epidemiology: data analysis.

Abstract: A brief review is given of data analysis methods for the identification and quantification of associations between environmental exposures and health events of interest. Data analysis methods are outlined for each of the study designs mentioned, with an emphasis on topics in need of further research. Particularly noted are the need for improved methods for accommodating exposure assessment measurement errors in analytic epidemiologic studies and for improved methods for the conduct and analysis of aggregate data (ecologic) studies.

On the Road: Marriage and Mortality in Malaysia

Abstract: Migration choices of husbands and wives in a dynamic and developing country are studied in the context of an economic model of the household. Data are drawn from the second wave of the Malaysia Family Life Survey. Elxploiting the retrospective histories, we compare moves that take place before marriage with those made during the marriage; among the latter, moves that are made with the spouse are distinguished from those made alone. The evidence indicates that male mobility is primarily economic in motivation and related to labor market factors. Moves by women, however, seem to be more closely related to fertility or family considerations. Migration is apparently not simply an individual decision; the attributes of the spouse are an important influence on mobility, albeit in an asymmetric manner. Moving toward a broader definition of the household, we find the characteristics of the parents, parents-in-law, and also the (relative) age and gender of siblings all influence mobility in a rich, if complex, way.

Does Head Start Make a Difference

Abstract: Although there is a broad hi-partisan support for Head Start, the evidence of positive longterm effects of the program is not overwhelming. Using data from the National Longitudinal Survey's Child-Mother file, we examine the impact of the program on a range of child outcomes. We compare non-parametric estimates of program effects with estimates from parametric models that control for selection by including mother fixed effects. This comparison suggests that studies that ignore selection can be substantially misleading; it also suggests that the impact of selection differs considerably across racial and ethnic groups. After controlling for selection, we find positive and persistent effects of participation in Head Start on the test scores of white and Hispanic children. These children are also less likely to have repeated a grade. We find no effects on the test scores or schooling attainment of African-American children. White children who attend Head Start are more likely to receive a measles shot, while African-American enrollees receive measles shots at an earlier age. African-American children who attend Head Start are also taller than their siblings. In a sample of the children's mothers, we find evidence that whites who attended Head Start as children are taller and have higher AFQT scores than their siblings who did not

The Demographic Transition in South Africa: Another Look at the Evidence from Botswana and Zimbabwe

Abstract: Botswana and Zimbabwe have been acclaimed as being on the vanguard of the demographic transition in sub-Saharan Africa. This paper examines the comparability of the CPS and the DHS data for each country and finds that part of the observed decline in aggregate fertility rates in both countries can be attributed to differences in sample composition. Women of the same cohort tend to be better educated in the second survey relative to the first. This fact explains part—but not all—of the observed fertility decline; for example, it appears to account for up to half the observed decline among women age 25–34 in 1984 in Zimbabwe.