The importance of being mature: the effect of demographic maturation on global per capita GDP

Given that savings behaviour and worker productivity have strong life-cycle components and given that demographic profiles vary across countries, population age structure should be linked to differences in levels of economic development. In this paper, we measure the economic importance of age structure variation for the global economy. We find that demographic maturation has been associated with nearly half of the evolution of global per capita GDP since 1960. We also find that age structure differences can account for just over half of the variation in worldwide per capita GDP (i.e. the lack of sigma convergence) observed since 1960.

Testing Evolutionary Hypotheses with Demographic Data

An ecological evolutionary viewpoint offers new perspectives on contemporary demographic problems in general and on population–environment issues in particular. In turn, rich and detailed human demographic data can help solve problems of interest in evolutionary theory. Such data have been analyzed in greatest detail in studies of traditional and historical societies. Evolutionary approaches using historical data go beyond small‐sample anthropological studies to the application of the evolutionary approach to large datasets, and illuminate important similarities between small‐scale traditional societies and large modern populations living in evolutionarily novel environments. This article provides a concise update of the breadth of questions and hypotheses of likely interest to demographers and others that evolutionary theorists address using a variety of traditional and historical datasets. It suggests opportunities for additional collaborative work between evolutionary theorists and historical demographers and highlights topics relevant to modern demography.     

Childhood family structure and young adult behaviors

This paper examines a wide variety of forms, and full histories, of family structure to test existing theories of family influences and identify needs for new theories. The focus is on links between childhood family structure and both completed schooling and risk of a nonmarital birth. Using a 27-year span of panel (PSID) data for U.S. children, we find that: (a) change is stressful, (b) timing during childhood is relevant, (c) adults other than parents are important, and (d) two more recently studied family structures (mother-with-grandparent(s) and mother-with-stepfather) do not fit the molds of existing theories. The findings suggest that new theories should consider allocation of resources and reasons people group into family structures. Received: 11 September 1998/Accepted: 27 March 2000     

Education and survival: Birth cohort,period, and age effects

Previous studies have found that educational differences in mortality are weaker among the elderly. In this study I examine whether either cohort or period effects may have influenced the interpretation of age effects. Six 10-year birth cohorts are followed over 30 years through decennial censuses. Differential survival is inferred from changes in the relative proportions of a cohort in each education category as the cohort ages. In cross-section, younger persons generally show stronger education effects on survival, although this pattern is clearer for women than for men. There is evidence of period effects. Within cohorts, relative survival tends to increase with age.     

Integrating Analysis and Communication Skills into the Decision Science Curriculum*

The teaching of decision sciences presupposes that careful attention is directed toward improving students' critical thinking and analytical skills. This paper presents an approach to teaching quantitative methods classes that focuses on developing student skills in the areas of analytical and critical thinking through written and oral communication. The approach requires very little additional instructor preparation time and does not require the instructor to make major changes in either the content or organization of the course. While the instructor's investment is minimal, the benefits to the students appear to be substantial.     

A Bayesian Approach for Analyzing Results of Vehicle Collision Tests

Certain motor vehicle safety standards stipulate a collision test speed and a set of performance criteria that vehicles must satisfy during or after the collision test. For example, Federal Motor Vehicle Safety Standard 301 requires a 30 mile per hour (mph) barrier collision and specifies a certain maximum allowable limit on the total spillage of fuel. Vehicle designs are required to meet this standard; however, when collision tests are conducted at speeds higher than the standard, vehicles do not always satisfy the performance criteria. This paper develops a mathematical model for estimating the probability of meeting the standard by using a Bayesian framework to incorporate engineering judgment with collision test results. The model is based on the idea that there are random features to a vehicle's ability to meet performance standards in a collision, especially at such elevated speeds. Example calculations are included to illustrate the estimation of the probability of meeting the standard and to compare it with a maximum likelihood approach.     

On the Joint Lot-Sizing Problem with Zero Setup Costs

In a recent paper, Pinto and Mabert [5] presented a lot-sizing rule and an improvement procedure for the joint lot-sizing problem with zero setup costs. We show that this procedure often yields infeasible schedules. We also present and discuss two interesting properties of the joint lot-sizing problem with zero setup costs. A numerical example to illustrate the second property is provided.     

Data Driven Modeling: An Application in Scheduling

This paper presents a data driven modeling (DDM) approach to certain types of optimization problems. DDM relinquishes control of the completed model to the user department rather than the operations research (OR) staff. The approach emphasizes development of models that are dependent on data maintained and understood by the users. The data base consists of coded user rules which describe when changes will occur in the problem structure and data which captures the generalization of the problem. Both the rules and data can be updated by user department personnel. These data drive a matrix generator controlled by the rules which uses the data base as input to generate the specific model formulation. This DDM system is designed by OR consultants or staff to allow independence of use along with low-cost and minimal-effort maintenance. The DDM approach is illustrated with an application to a real-world medical scheduling problem.     

Social Background Differences in Early Family Behavior

Social background has historically been recognized as a major factor influencing family behavior, though recent work has largely emphasized racial/ethnic influences. Here we use 1994 – 1995 and 2001 – 2002 Add Health data to examine the cohabitation, first marriage, and first birth experience of young women. In a multistate life table context, hypothetical cohorts specified in terms of race and mother’s education are followed, from age 11 to age 24, as they move through 6 family‐related statuses. The results indicate that, for both Black and White women, a higher level of maternal education is generally associated with less cohabitation, less marriage, fewer first births, and a higher percentage of women who experience none of those transitions before age 24. Racial and social background differences are conceptually and empirically distinct. Because mother’s education is associated with substantially different trajectories of early family behavior for both Blacks and Whites, we argue that social background merits increased attention in research on contemporary American family patterns.     

“Which One Is Yours?”: Children and Ethnography

This paper explores roles that children play in ethnographic research. Based on the limited literature on children in the field, and drawing on examples from ethnographies across disciplines, I identify four roles for children: 1) as “wedges,” or as instrumentally important in helping adult ethnographers gain access in various ways; 2) as collaborators; 3) as objects of study; and 4) as subjects of study. I also discuss the ways in which these roles illuminate key methodological issues in ethnography, like reflexivity, ethics, and agency. The paper synthesizes and integrates previously disconnected research on the presence of children in the field with ethnographies in which children and childhood are the topics of research. I draw on my own fieldwork experiences for further illustration.