Demographic Influences On The Number Of Children At School Entry Ages, With Examples From Three States

When demographic rates are in flux, each age group within a regional population grows at a different rate. This paper analyzes the effects of changes in fertility, mortality, and net migration patterns on the growth of school entry-age populations in three states (Florida, South Carolina, and West Virginia) over the period 1950-1990. Fertility changes have had the largest influence on growth of these young populations, as common sense suggests. Changing migration patterns have been quite important, however, in explaining intertemporal and interspatial variations in growth rates. Furthermore, migration's effects on age-specific growth rates can be counterintuitive. Most importantly, sustained net in-migration does not necessarily generate positive growth of age-specific populations within a state. We discuss some implications for policy and for improving population projections.