We show that Bayesian population reconstruction, a recent method for estimating past populations by age, works for data of widely varying quality. Bayesian reconstruction simultaneously estimates age-specific population counts, fertility rates, mortality rates, and net international migration flows from fragmentary data, while formally accounting for measurement error. As inputs, Bayesian reconstruction uses initial bias-reduced estimates of standard demographic variables. We reconstruct the female populations of three countries: Laos, a country with little vital registration data where population estimation depends largely on surveys; Sri Lanka, a country with some vital registration data; and New Zealand, a country with a highly developed statistical system and good quality vital registration data. In addition, we extend the method to countries without censuses at regular intervals. We also use it to assess the consistency of results between model life tables and available census data, and hence to compare different model life table systems. 相似文献
Demographers and those concerned with population policy are increasingly focusing on the steep fertility declines that occurred
in developed countries from the 1960s and the consequent widespread below-replacement fertility levels. The decline has been
termed the Second Demographic Transition. This paper argues that the recent demographic change can best be understood and
analyzed if we broaden the concept to include the first demographic transition, and the three demographically more settled
periods preceding, separating, and following the two fertility transitions. These more settled periods or “compromises” are
examined to ascertain their nature and so to help predict the likely developments in the present or third compromise. It is
argued that the third compromise has now extended for 20 years with little movement in fertility rates or other socioeconomic
behavior which has been said to be associated with the second transition, and that this provides sufficient evidence for analysis.
The approach has two key aspects. First, it is confined in Europe to countries that distinctly experienced the full five demographic
periods, namely northwestern and central Europe. Second, the analysis gains strength by including non-European countries that
progressed through all five stages, namely the English-speaking countries of overseas European settlement: USA, United Kingdom,
Australia, and New Zealand. 相似文献
This article critiques a recent U.N. Population Division report, Replacement Migration: Is it a Solution to Declining and Ageing Populations? The report explores the use of increased immigration to bolster future population size and change age distribution patterns in a group of developed countries. Fertility rate declines and lengthening life expectancies associated with demographic transition inevitably yield an aging population and a falling potential support ratio (PSR), a situation which some demographers and economists view with alarm. As the U.N. report itself suggests, replacement migration can only temporarily delay population aging and decline. These issues are ultimately better addressed through changes in retirement policy. Population projections should be used only with great caution in designing long-term demographic policy. In particular, some assumptions used to make the U.N. projections are questionable, and even minor changes in those assumptions would yield substantially different policy conclusions. Replacement migration also raises difficult environmental questions by moving large numbers of people from low to high per-capita consumption nations. Modest population decline, particularly in more developed countries, may have significant local and global environmental and climate policy benefits.