Intrinsically dynamic models (IDMs) depict populations whose cumulative growth rate over a number of intervals equals the product of the long term growth rates (that is the dominant roots or dominant eigenvalues) associated with each of those intervals. Here the focus is on the birth trajectory...

Formal demography has yet to move beyond assuming that demographic rates are constant over time, an assumption that is both unrealistic and constraining. To generalize the fixed rate stable model to the changing rate dynamic model, this paper explores the mathematical regularities that underlie...

Many studies have examined Keyfitz’s population momentum, a special case of inertia in long-term population size resulting from demographic transition to the stationary population growth rate. Yet, population inertia can be produced by any demographic perturbation (i.e., not just perturbations...

When fertility increases in a previously stable population, the new stable population will be younger than the old one, and the two age distributions will cross at the mean age of the populations.

The age-specific growth function of an observed population and the reproductive value function based on the population´s current vital rates determine the intrinsic rate of growth implied by those vital rates through the simple relationship given in equation (1). That equation establishes the...

A sample covering 204,394 blocks from the 1990 U.S.Census permits measurement of residual heterogeneity from local area to local area after controlling by stratification for demographic characteristics such as race, ethnicity, age, sex as well as geographic characteristics such as region and...

By marrying and raising children, parents participate in a system of gift-exchange in which the gifts in question are human lives, and the parties to the exchange are the kinship groups recognised in the society concerned. Fertility reflects the attitudes of prospective parents to their place in...

Our study describes fundamental changes in childbearing behavior in Hungary. It documents current postponement of entry into motherhood (first birth) and uncovers signs of delay in second birth. We place the behavioral modifications into historical time and reveal the basic role of the...

Period life expectancy has increased more slowly than its cohort counterpart. This paper explores the differences between life expectancies at a given time (the gap) and the time required for period life expectancy to reach the current level of cohort life expectancy (the lag). Additionally, to...