title: Four themes in fertility research.
abstract: This study is concerned with four main themes that have been combined to describe U.S. fertility trends since 1920.  These themes are identified as a time adjustment mechanism, income, the wife's labor force activities, and some intergenerational factor.  "In order to obtain an unambiguous picture each theme will be represented by only one variable.  After selecting the variables and estimating a model, an examination of the changing role these variables have had in explaining changes in fertility (the total fertility rate) throughout much of this century will be made.  Finally, the implications these themes have for future fertility will be examined."  The authors conclude that "in interpreting historical U.S. fertility rates, the results seem to indicate that much of the early decline in U.S. fertility was due to falling infant mortality.  After the Second World War, fertility rose sharply as the age-structure variable declined and income rose.  Eventually both women's labor force participation rates and the age-structure variable rose and, consequently, fertility fell."  They also suggest that the age structure variable may cause a temporary upward swing in fertility in the near future.
authors.forename: M P
authors.initials: MP
authors.lastname: Shields
authors.forename: R L
authors.initials: RL
authors.lastname: Tracy
mesh_terms: D000569:Americas; D003710:Demography; D019049:Developed Countries; D003906:Developing Countries; D004467:Economics; D004651:Employment; D005298:Fertility; D006280:Health Workforce; D007182:Income; D008962:Models, Theoretical; D009656:North America; D011153:Population; D011157:Population Dynamics; D012106:Research; D012959:Socioeconomic Factors; D013997:Time Factors; D014481:United States
keywords: Americas; Demographic Factors; Developed Countries; Developing Countries; Economic Factors; Fertility--changes; Historical Survey; Human Resources; Income; Intergenerational Transfers; Labor Force--women; Microeconomic Factors; Models, Theoretical; North America; Northern America; Population; Population Dynamics; Research Methodology; Socioeconomic Factors; Time Factors; United States