Income sufficiency v. poverty Results from the United States and The Netherlands

The purpose of this paper is to further the understanding of subjective measures used to assess poverty and to add to the literature on poverty measurement methodology. In particular, the paper focuses on the minimum income question (MIQ) first proposed by Goedhart and colleagues (1977). Data from the U.S. Consumer Expenditure Survey and from a Dutch newspaper survey are used. The primary contribution of the paper is the inclusion of household expenditures as additional explanatory variables of minimally necessary income. Significant differences between the coefficients of several categories of expenditures, particularly for leisure, appear to reveal differences in the interpretation of the minimum income question by respondents. Thus, we question the underlying assumption of the MIQ that everyone adheres the same welfare meaning to the phrase “minimally necessary income,” and conclude that the resulting thresholds should not be used as to measure poverty before further research has been carried out to explore what respondents are thinking when they answer questions such as the MIQ.     

Rural–Urban Child Height for Age Trajectories and Their Heterogeneous Determinants in Four Developing Countries

The large literature on health differentials between rural and urban areas relies almost exclusively on cross-sectional data. Bringing together the demographic literature on area-level health inequalities with the bio-physiological literature on children’s catch-up growth over time, this paper uses panel data to investigate the stability and origins of rural–urban health differentials. Using data from the Young Lives longitudinal study of child poverty, I present evidence of large level differences but similar trends in rural versus urban children’s height for age in four developing countries. Further, observable characteristics of children’s environment such as their household wealth, mother’s education, and epidemiological environment explain these differentials in most contexts. In Peru, where they do not, children’s birthweight and mothers’ health and other characteristics suggest that initial endowments—even before birth—may play an important role in explaining "residual" rural–urban child height inequalities. These latter results imply that prioritizing maternal nutrition and health is essential—particularly where rural–urban height inequalities are large. Interventions to reduce area-level health inequalities should begin even before birth.     

Forensic demography and civil rights

In the summer of 1965, the legislature of the state of Mississippi passed a law which required children whose parents were living in another state to pay up to $350 tuition in order to attend public school. On the belief that this law discriminated against Negroes and was therefore unconstitutional, the Department of Justice began litigation procedures to repeal it. But evidence was needed to prove that the law was in fact discriminatory. The lawyers contacted demographers at the Bureau of the Census to provide data to determine if the majority of persons affected were Negro and too poor to pay the tuition. They sought information which could tell them, ideally, how many parents of children in Mississippi had left the state and what the economic position and racial characteristics of the children were.An attempt was made to get this information from already published sources, such as census reports and other research findings. These could give a hurried impression of the situation but could not deal directly with the issue of the whereabouts of parents not living with their children, since such a question had not been asked in the 1960 Census. An additional bit of information was obtained from the NAAGP Legal Defense and Education Fund in Jackson, Mississippi, from forms showing characteristics of persons actually affected by the law. But this limited sample did not provide evidence solid enough upon which to build a case.It was decided to rely on a retabulation of 1960 Census records to describe accurately the base population from which children with parents out of state would be drawn-namely, the children not living with either parent. This showed that of all school-age children living without either parent, 82 percent are Negro. The average Negro household, which contains at least one "parentless" child, houses 6.8 persons and has an annual income of $1,429. This allows less than $250 annually per person. Tuition for just one child eats up more than one person's yearly allotment. These data showed that the law, in fact, did discriminate racially, since most of the persons affected were Negro and too poor to pay tuition.This was one instance in which demographers were able to use their special skills in implementing public policy-notably, the law.     

Change, continuity or cycles: The population turnaround in New South Wales

This study examines population flows from Sydney and other regions to perimetropolitan and coastal areas of New South Wales, the two main foci of the population turnaround since 1971. It uses census internal migration statistics for the five intercensal periods between 1971 and 1996, and estimated resident population statistics between 1997 and 2000. Fluctuating trends are described with respect to variations in age structures of migration flows and net migration gains by SLAs in coastal areas over time. Evidence of fluctuating trends is evaluated in relation to population structure change and local socio-economic multipliers in turnaround areas. The turnaround is far mor than a net migration gain from large metropolitan areas; it is also associated with interregional migration which avoids metropolitan areas, and which is at least in part environment- and amenity-related. The experience of some other countries, such as the USA where net migration reversals in population turn-around regions have occurred, has not been replicated in Australia. While elements of explanation for the complex cumulative causation process of the population turnaround in Australia are discussed, including the issues of fluctuating or cyclical trends, much more understanding of the economic and social factors involved is required.     

Life table analysis of the green rice leafhopper,Nephotettix virescens (distant) (Hemiptera: Cicadellidae), and efficient vector of rice tungro disease in asynchronous rice fields in Indonesia

Summary Population dynamics ofNephotettix virescens was studied in 17 paddy fields transplanted at intervals of about 1 month in 1988–1990. The adult density was highest either in the immigrant or the 1st generation and sharply decreased to the 2nd generation. The survival rate of the 1st generation was lowest in the transition season when areal population density increased. Key factor analysis revealed that the nymphal and adult mortality of the 1st generation (kn) was the principal source of population fluctuations. No significant correaltion was found between kn and natural enemy density, natural enemy density/healthy egg density, or the precipitation during the nymphal period. On these bases adult emigration was suspected to be the key factor. Areal population build-up ofN. virescens in the transition season was considered to occur as a result of increasing immigration to young stages of rice. Contribution from Indonesia-Japan Joint Program on Food Crop Protection (ATA 162), which was implemented by the Directorate of Food Crop Protection, Ministry of Agriculture, Indonesia and Japan International Cooperation Agency, Japan.     

Differentiation of voivodeships in terms of the number of children in the household

The author attempts to answer the question, "Are the numbers of households [in Poland] with specific numbers of supported children (structures) in the total number of households similar or dissimilar in all voivodeships, and where [are these] identical (similar) or dramatically different?" Results indicate that "the most differentiated voivodeships, in terms of the number of children below 24 years of age supported by households, were voivodeships of north-eastern and south-eastern Poland. In the case of male heads of households the number of voivodeships making up areas of the highest differentiation regarding the number of children below 24 years is definitely bigger than for the female heads of households."     

The dynamics of outbreaks: Further simulation experiments with the western tent caterpillar

Summary A stochastic model of western tent-caterpillar populations on southern Vancouver Island was used to assess conditions leading to outbreaks. Three qualitatively different populations-declining, minimal, and recovering-were exposed to six-year climatic sequences incorporating various combinations of good, bad, and mediocre spring weather. Starting populations were either distributed randomly or concentrated in and around small-, medium-, or large refuges. The results showed that virtually any type of population could temporarily increase in numbers during two highly favorable springs. Only a very few vigorous populations, however, could sustain the momentum required to surge to outbreak proportions. No low-quality population could do so. And even vigorous populations could not achieve outbreak status unless they were initially concentrated in a sufficiently large refuge that was close enough to potentially suitable habitats to permit rapid immigration into such places as soon as their local climates improved. The concept of “climatic release” of insect populations is discussed in the light of these findings. The results demonstrate that climatic release is inextricably linked with a population's qualitative profile and spatial distribution. Order of authorship determined by chance.