The demographic evolution of human populations: The role of selection and environmental factors

Selection (genetic and cultural) and environmental variation are the principal mechanisms determining patterns of demographic change in human populations. Conditions exist under which the nature and intensity of these forces can be inferred from temporal trends in the demographic variables. These conditions, which can be expressed in terms of relations between the Malthusian parameter and population entropy, provide a means for evaluating the effect of selective and nonselective factors on demographic trends in human populations. The distinction between the roles of selection and environmental factors is illustrated by a study of the demographic transition in Sweden (1778-1965). This study shows that demographic changes during the pre- and posttransitional phases are determined mainly by environmental factors, whereas the changes during the transitional phase are mainly due to cultural selection. This analysis provides, for all three phases of the demographic transition, quantitative measures of the intensity of the forces (selective and nonselective) acting on both mortality and fecundity distributions.     

Empirical characteristics of legal and illegal immigrants in the USA

We combine the New Immigrant Survey (NIS), which contains information on US legal immigrants, with the American Community Survey (ACS), which contains information on legal and illegal immigrants to the USA. Using an econometric methodology proposed by Lancaster and Imbens (J Econ 71:145–160, 1996) we compute the probability for each observation in the ACS data to refer to an illegal immigrant, conditional on observed characteristics. These results are novel, since no other work has quantified the characteristics of illegal immigrants from a random sample representative of the population. Using these conditional probability weights on the ACS data, we are able to uncover some interesting facts on illegal immigrants. We find that, while illegal immigrants suffer a large wage penalty compared to legal immigrants at all education levels, the penalty decreases with education. We also find that the total fertility rate among illegal immigrant women is significantly higher than that among legal ones, in particular for middle and higher educated women. Looking at the sector of activity, we document that the sectors attracting most illegal immigrants are constructions and agriculture. We also generate empirical distributions for state of residence, country of origin, age, sex, and number of legal and illegal immigrants. Our forecasts for the aggregate distribution of legal and illegal characteristics match imputations by the Department of Homeland Security.     

Spatial weighting improves accuracy in small-area demographic forecasts of urban census tract populations

Existing research in small-area demographic forecasting suffers from two important limitations: (1) a paucity of studies that quantify patterns of error in either total or age/sex-specific estimates and (2) limited methodological innovation aimed specifically at improving the accuracy of such forecasts. This paper attempts to fill, in part, these gaps in existing research by presenting a comparative evaluation of the accuracy of standard and spatially-weighted Hamilton–Perry forecasts for urbanized census tracts within incorporated New Mexico municipalities. These comparative forecasts are constructed for a 10-year horizon (base 1 April 2000 and target 1 April 2010), then compared to the results of the 2010 Census in an ex post facto evaluation. Results are presented for the standard Hamilton–Perry forecasts as well as two sets that incorporate two common variants of spatial weights to improve forecast accuracy. Findings are discussed in the context of what is currently known about error in small-area demographic forecasts and with an eye toward continued innovations.     

Nativity,duration of residence and the life course pattern of extended family living in the USA

Recent changes in US immigration policy anddomestic welfare policies affecting immigrants haveled to concerns that families will face greaterpressure to provide for extended family members.Extended family households are important resources fornew immigrants to the USA and an integral part of theadaptive strategy of immigrants. This paper examinesthe competing roles of duration of residence in theUSA, aging and changes over time in explainingincreases in extended family living between 1980 and1990. The results from a pooled sample of 1980 and1990 Census data indicate that recent arrivals aremore likely to share households with extended kin butit is older immigrants who face an increasedlikelihood of such coresidence over time. Multinomiallogistic regression analysis demonstrates that thelife course pattern of coresidence remains whenchanges in socioeconomic status are controlled. Theresults suggest that policy changes limiting publicfunds available to new arrivals will have a largerimpact on families sponsoring older family members.     

The importance of demographic analyses in state- and local-level policy evaluations: A case study analysis of property taxes in Texas,USA

The reluctance of policy-makers to incorporate detailed demographic analyses in policy analyses often means that population composition is ignored in state and local policy evaluations. This article uses standard demographic projection, standardization and rate decomposition techniques to examine the implications of changing population composition for the property tax revenue base of Texas. The authors find that if current socioeconomic differentials persist into the future, projected compositional changes in the household population of Texas will significantly impact property tax revenues. Thus revenue projections based on aggregate growth and current average property value would seriously overestimate future property tax revenues in Texas because changes in the composition of the population lead to disproportionate growth in households likely to live in lower valued housing unite. The results indicate that the continuing focus of state and local policy-makers on changes in population size alone may be ill-advised and demonstrate the increasing importance of local- and state-level demographic analysis in a period of increasing Federal devolution of service provision.     

Understanding the demographic characteristics of urban men who have sex with men

We examined migration, closetedness, and family structure explanations of demographic profiles of urban men who have sex with men (MSM) using data from the Urban Men's Health Study and the Public Use Microdata Sample of the U.S. Census. The data suggested that the demographic profiles of urban MSM reflect a large in-migrating white, often young adult, population without children. Closetedness, an oft-cited bias in MSM population studies, did not significantly impact demographic patterns with minor exceptions. MSM urban subpopulations have demographics that differ substantially from the general population of the cities in which they reside.     

The demographic impact of Partition in the Punjab in 1947

We use data from the 1931, 1941, and 1951 censuses of India and the 1951 census of Pakistan to examine the demographic consequences of Partition in the Punjab in 1947. Had growth rates for the period 1931-41 for the Punjab as a whole continued to 1951, the population of the Punjab would have been 2.9 million larger than that recorded in 1951. Population losses from migration and mortality above age 20 were approximately 2.7 million greater between 1941 and 1951 than would have been predicted by loss rates between 1931 and 1941. We estimate a net Partition-related population movement out of the combined Punjab of about 400,000. We conclude from several lines of analysis that Partition-related population losses in the Punjab, either from deaths or unrecorded migration, were in the range 2.3-3.2 million. Partition was also marked by a dramatic religious homogenization at the district level.     

The demographic impact of Partition in the Punjab in 1947

We use data from the 1931, 1941, and 1951 censuses of India and the 1951 census of Pakistan to examine the demographic consequences of Partition in the Punjab in 1947. Had growth rates for the period 1931–41 for the Punjab as a whole continued to 1951, the population of the Punjab would have been 2.9 million larger than that recorded in 1951. Population losses from migration and mortality above age 20 were approximately 2.7 million greater between 1941 and 1951 than would have been predicted by loss rates between 1931 and 1941. We estimate a net Partition-related population movement out of the combined Punjab of about 400,000. We conclude from several lines of analysis that Partition-related population losses in the Punjab, either from deaths or unrecorded migration, were in the range 2.3–3.2 million. Partition was also marked by a dramatic religious homogenization at the district level.     

The development and use of demographic models

In this review, we first examine two classical demographic models - conventional life tables and stable populations - and a modern generalization of stable population theory; we then discuss mathematical models of conception and birth. These models involve purely mathematical relations in formal demography as opposed to empirical regularities. Next we consider model age schedules of mortality, nuptialitiy, marital fertility, fertility, and migration that are explicitly based on such empirical patterns. We close this empirical section with a discussion of model stable populations, which are based on model life tables. We next examine the use of demographic models in forecasting future mortality, nuptiality, and fertility and in population projection. Following a discussion of microsimulation models, which gives us the opportunity to mention model age schedules of post partum amenorrhoea and of sterility, we close with observations about the purposes and uses of demographic models.     

The analysis of linkages in demographic theory

Many seemingly different questions that arise in the analysis of population change can be phrased as the same technical question: How, within a given demographic model, would variable y change if the age- or time-specific function f were to change arbitrarily in shape and intensity? At present demography lacks the machinery to answer this question in analytical and general form. This paper suggests a method based on modern functional calculus for deriving closed-form expressions for the sensitivity of demographic variables to changes in input functions or schedules. It uses this “linkage method” to obtain closed-form expressions for the response of the intrinsic growth rate, birth rate, and age composition of a stable population to arbitrary marginal changes in its age patterns of fertility and mortality. It uses it also to obtain expressions for the transient response of the age composition of a nonstable population to time-varying changes in the birth sequence, and to age-specific fertility and mortality patterns that change over time. The problem of “bias” in period vital rates is also looked at.     

The variance of population characteristics in stable populations, with applications to the distribution of income

Summary Stable population theory has recently been used to analyse the effects of changes in fertility and mortality on economic variables such as income per head. In this paper more general results are derived to describe the effects of changing vital rates on the variance and higher moments of the distribution of some age-dependent variable. Simple analytical expressions are derived which decompose the effects of changes in age structure into the effects on inter-cohort and intra-cohort variance. The results are easily applied to standard measures of the distribution of income. By combining the analytical results with actual age profiles of income and income variance from the United States and Brazil it is observed that both the magnitude and direction of the effects of population growth on measured inequality are sensitive to the specific age profiles used. The most surprising result is that the Brazilian age profiles suggest that higher growth rates may actually reduce measured inequality, although the effect is relatively small.     

Retirement against the demographic trend: More older people living longer, working less, and saving less?

The American population is aging rapidly and individuals are living longer. Yet Americans are saving less and older workers are leaving the labor force at younger and younger ages. The accelerated drop in labor force participation corresponds roughly to the introduction of Social Security and the adaption of employer-provided pension plans. I have illustrated that Social Security and employer-provided pension plans provide substantial incentive to leave the labor force early. The quantitative effect of this inducement is illustrated by simulating the effects of changes in pension plan and Social Security provisions on the retirement decisions of employees in a large firm, who are covered by a typical defined benefit pension plan. Scheduled Social Security changes would have little effect on the retirement decisions of employees with a typical defined benefit pension plan like the one considered here. But if the pension plan provisions were changed to correspond to the Social Security changes, the effect would be very large. And, although not contemplated by current legislation, it is clear that an increase in the Social Security early retirement age would have a substantial effect on the early retirement rates of the large number of employees not covered by a pension plan.     

人口学界对“以人为本”思想的理解和研究

“以人为本”思想起源甚早,国内外许多领域的专家、学者以及实际工作者对这一思想都有过阐述和研究。从我国人口学的视角出发,结合三十多年以来我国计划生育政策的实践与发展,系统地总结了国内人口学界对“以人为本”思想的理解和研究。     

Population change in Meso-America: The Tip of the demographic Iceberg

This paper examines the demographic situation in Mexico and Central America (Meso-America) and looks at the momentum for growth implied by recent population shifts. Despite successes in reducing fertility levels in many Meso-American countries, the dramatic declines in mortality among infants and children have given rise to a "death dearth" that is contributing to a new "baby boom" in these countries; thus our subtitle, "The Tip of the Iceberg."The impacts of such population growth on education, the economy and migration are considered in some detail. The anticipated inability of country economies to provide jobs for the thousands of young adults entering the labor force in future years could result in significant increases in the number seeking to migrate in a northerly direction. Thus, the United States is also vitally interested in the demographic shifts taking place south of its border.The need for a more unified regional approach to some of the social and economic problems facing these nations is pointed out as is the need for a more rational immigration policy on the part of the United States in light of the potential increase in immigration in future years.     

The demographic context of recent change in the structure of American households

This article examines recent changes in the structure of American households within the context of broad population changes. Decreases in married-couple households and increases in single-parent households are almost entirely due to the changing patterns of marriage, divorce, fertility, and child custody; headship rates for families have remained relatively stable. Increases in single-person and other nonfamily households are due to increases in the size of the unmarried, childless population and to the aging of this population. Increasing propensities to live alone or with nonrelatives were observed between 1970 and 1980, but these behavioral changes have abated during the early 1980s.     

The demographic viewpoint in the vital and health statistics monographs of The American Public Health Association

The plan calls for monographs on 16 specific topics and a review volume. The specific topics include a monograph on fertility, another on marriage and divorce, and one on social and economic factors in mortality, all of which are of obvious demographic interest. The core of the development of the monographs dealing with the disease topics, and accidents, homicide, and suicide, is a tabulation program involving specific and age-adjusted death rates based upon the deaths in the United States for the three year period 1959-61 and the 1960 census of population. The program called for a set of standard tabulations common to each monograph and also a set of special tabulations tailored to meet the particular needs for each topic as specified by its authors. This wealth of demographic detail regarding mortality in the United States during 1959-61 fills only one aspect of its health picture. To fill out the health picture, use is being made of the great volume of morbidity data out of the National Health Interview and Examination Surveys and a wide variety of other specialized surveys. In all of these, the findings are invariably described in terms of the demographic characteristics of age and sex, and frequently in terms of such social-economic variables as education, income, work status, and occupational class.A large part of the content of the monograph on social and economic factors in mortality will come out of available results of the 1960 census-death certificate matching study at the University of Chicago. One important feature of this monograph, not contained in the Chicago study, is a regression and correlation analysis of total mortality in 202 Standard Metropolitan Statistical Areas in relation to a large number of social, economic, and climatic factors. Among the features in the monograph on fertility are chapters on the medical and biological characteristics of births, fecundity and family planning, and an analysis of cohort fertility trends. The monograph on marriage and divorce will make use of the detailed tabulations from the 1960 census on marital status in relation to education, race, parentage, earnings and other classifications of individuals and of husband and wife in married couples. It will also contain a matching study of divorce records in certain states for a short period before the census of 1960 with the returns in the census. The project is supported by a grant from the United States Public Health Service (CH 00075; formerly RG 08262). Publication will be by the Harvard University Press.