Quantifying Economic Dependency

In this paper we compare several types of economic dependency ratios for a selection of European countries. These dependency ratios take into account not only the demographic structure of the population, but also the differences in age-specific economic behaviour such as labour market activity, income and consumption as well as age-specific public transfers. In selected simulations where we combine patterns of age-specific economic behaviour and transfers with population projections, we show that in all countries population ageing would lead to a pronounced increase in dependency ratios if present age-specific patterns were not to change. Our analysis of cross-country differences in economic dependency demonstrates that these differences are driven by both differences in age-specific economic behaviour and in the age composition of the populations. The choice of which dependency ratio to use in a specific policy context is determined by the nature of the question to be answered. The comparison of our various dependency ratios across countries gives insights into which strategies might be effective in mitigating the expected increase in economic dependency due to demographic change.     

Coherence principles in interval‐based dose finding

This paper studies the notion of coherence in interval‐based dose‐finding methods. An incoherent decision is either (a) a recommendation to escalate the dose following an observed dose‐limiting toxicity or (b) a recommendation to deescalate the dose following a non–dose‐limiting toxicity. In a simulated example, we illustrate that the Bayesian optimal interval method and the Keyboard method are not coherent. We generated dose‐limiting toxicity outcomes under an assumed set of true probabilities for a trial of n=36 patients in cohorts of size 1, and we counted the number of incoherent dosing decisions that were made throughout this simulated trial. Each of the methods studied resulted in 13/36 (36%) incoherent decisions in the simulated trial. Additionally, for two different target dose‐limiting toxicity rates, 20% and 30%, and a sample size of n=30 patients, we randomly generated 100 dose‐toxicity curves and tabulated the number of incoherent decisions made by each method in 1000 simulated trials under each curve. For each method studied, the probability of incurring at least one incoherent decision during the conduct of a single trial is greater than 75%. Coherency is an important principle in the conduct of dose‐finding trials. Interval‐based methods violate this principle for cohorts of size 1 and require additional modifications to overcome this shortcoming. Researchers need to take a closer look at the dose assignment behavior of interval‐based methods when using them to plan dose‐finding studies.     

The role of reciprocation in social network formation,with an application to LiveJournal

This paper deals with the role of reciprocation in the formation of individuals’ social networks. We follow the activity of a panel of bloggers over more than a year and investigate the extent to which initiating a relation brings about its reciprocation. We adapt a standard capital investment model to study how reciprocation affects the build-up of the individual social capital of bloggers, as measured by their links and interactions with others. This allows us to measure the role of content production and relationship building in the dynamics of online social networks and to distinguish between the social networking and media aspects of blogging.     

Are Individuals’ Desired Family Sizes Stable? Evidence from West German Panel Data

Using West German panel data constructed from the 1988 and 1994/1995 wave of the DJI Familiensurvey, we analyze the stability and determinants of individuals’ total desired fertility. We find considerable variation of total desired fertility across respondents and across interviews. In particular, up to 50% of individuals report a different total desired fertility across survey waves. Multivariate analysis confirms the importance of background factors including growing up with both parents, having more siblings, and being Catholic for preference formation. Consistent with the idea that life course experiences provide new information regarding the expected costs and benefits of different family sizes, the influence of background factors on total desired fertility is strong early in life and weakens as subsequent life course experiences, including childbearing, take effect. Accounting for unobserved individual heterogeneity, we estimate that an additional child may increase the total desired fertility of women with children by 0.14 children, less than what conventional estimates from cross-sectional data would have suggested.     

Slow‐fast dynamics in a model of population and resource growth

Models of the interaction of population, the economy, and the environment often contain nonlinear functional relationships and variables that move at different speeds. These properties foster apparent unpredictabilities in system behaviour. Using a simple deterministic model of demographic, economic and environmental interactions we illustrate the usefulness of geometric singular perturbation theory in environmental population economics. In contrast to local stability analysis, the theory of slow‐fast dynamics helps to gain new insights into the global behaviour of the system. In particular, the knowledge of the basins of attraction of the stationary states enables one to determine the regions of sustainable future paths of resources and population.     

Transition to Parenthood: The Role of Social Interaction and Endogenous Networks

Empirical studies indicate that the transition to parenthood is influenced by an individual’s peer group. To study the mechanisms creating interdependencies across individuals’ transition to parenthood and its timing, we apply an agent-based simulation model. We build a one-sex model and provide agents with three different characteristics: age, intended education, and parity. Agents endogenously form their network based on social closeness. Network members may then influence the agents’ transition to higher parity levels. Our numerical simulations indicate that accounting for social interactions can explain the shift of first-birth probabilities in Austria during the period 1984 to 2004. Moreover, we apply our model to forecast age-specific fertility rates up to 2016.     

Fertility and women's employment reconsidered: a macro-level time-series analysis for developed countries, 1960-2000

This paper examines causality and parameter instability in the long-run relationship between fertility and women's employment. This is done by a cross-national comparison of macro-level time-series data from 1960 to 2000 for France, West Germany, Italy, Sweden, the UK, and the USA. By applying vector error correction models (a combination of Granger-causality tests with recent econometric time-series techniques) we find causality in both directions. This finding is consistent with simultaneous movements of both variables brought about by common exogenous factors such as social norms, social institutions, financial incentives, and the availability and acceptability of contraception. We find a negative and significant correlation until about the mid-1970s and an insignificant or weaker negative correlation afterwards. This result is consistent with a recent hypothesis in the demographic literature according to which changes in the institutional context, such as changes in childcare availability and attitudes towards working mothers, might have reduced the incompatibility between child-rearing and the employment of women.     

Emotion Work,Shame, and Post-Soviet Women Entrepreneurs: Negotiating Ideals of Gender and Labor in a Global Economy

Drawing on ethnographic research among Russian women traders or “shuttle traders” (chelnoki), I examine discourses on shame as a type of emotion work and consider links to ideal gender roles among Russian women entrepreneurs. In a post-Soviet era increasingly shaped by transnational mobility, as well as by a persistent legacy of Soviet sensibilities, a focus on emotion among women traders provides an ideal lens for considering what travels between eras marked by distinct ideologies, between nation-states, and between public and domestic spaces. A discourse of shame links Soviet sensibilities of proper labor and contemporary gender sensibilities that continue to elevate men as breadwinners; thus, a focus on shame enables us to see the contradictory ways in which women are positioned in local and global economies in the 2000s. This case shows how Russian women's insertion into the global economy beginning in the early 1990s has required emotion work that is similar to that required in other locations where global capitalism has brought about reconfigurations of work lives and required people to renegotiate gender roles, expressions of power, and the meaning of labor in their lives.     

Union Instability as an Engine of Fertility? A Microsimulation Model for France

Opportunities for conceiving and bearing children are fewer when unions are not formed or are dissolved during the childbearing years. At the same time, union instability produces a pool of persons who may enter new partnerships and have additional children in stepfamilies. The balance between these two opposing forces and their implications for fertility may depend on the timing of union formation and parenthood. In this article, we estimate models of childbearing, union formation, and union dissolution for female respondents to the 1999 French Etude de l’Histoire Familiale. Model parameters are applied in microsimulations of completed family size. We find that a population of women whose first unions dissolve during the childbearing years will end up with smaller families, on average, than a population in which all unions remain intact. Because new partnerships encourage higher parity progressions, repartnering minimizes the fertility gap between populations with and those without union dissolution. Differences between the two populations are much smaller when family formation is postponed—that is, when union formation and dissolution or first birth occurs after age 30, or when couples delay childbearing after union formation.     

Timing, Sequencing, and Quantum of Life Course Events: A Machine Learning Approach

In this paper we discuss and apply machine learning techniques, using ideas from a core research area in the artificial intelligence literature to analyse simultaneously timing, sequencing, and quantum of life course events from a comparative perspective. We outline the need for techniques which allow the adoption of a holistic approach to life course analysis, illustrating the specific case of the transition to adulthood. We briefly introduce machine learning algorithms to build decision trees and rule sets and then apply such algorithms to delineate the key features which distinguish Austrian and Italian pathways to adulthood, using Fertility and Family Survey data. The key role of sequencing and synchronization between events emerges clearly from the analysis. Billari F.C., Fürnkranz J., et Prskawetz A., 2006. Calendrier, séquence et intensitédes événements du cycle de vie : une application des techniques d’apprentissage par machine. Revue Européenne de Démographie, 22: 37–65