Francesco C. Billari

Advances in development reverse fertility declines

During the twentieth century, the global population has gone through unprecedented increases in economic and social development that coincided with substantial declines in human fertility and population growth rates. The negative association of fertility with economic and social development has therefore become one of the most solidly established and generally accepted empirical regularities in the social sciences. As a result of this close connection between development and fertility decline, more than half of the global population now lives in regions with below-replacement fertility (less than 2.1 children per woman). In many highly developed countries, the trend towards low fertility has also been deemed irreversible. Rapid population ageing, and in some cases the prospect of significant population decline, have therefore become a central socioeconomic concern and policy challenge. Here we show, using new cross-sectional and longitudinal analyses of the total fertility rate and the human development index (HDI), a fundamental change in the well-established negative relationship between fertility and development as the global population entered the twenty-first century. Although development continues to promote fertility decline at low and medium HDI levels, our analyses show that at advanced HDI levels, further development can reverse the declining trend in fertility. The previously negative development–fertility relationship has become J-shaped, with the HDI being positively associated with fertility among highly developed countries. This reversal of fertility decline as a result of continued economic and social development has the potential to slow the rates of population ageing, thereby ameliorating the social and economic problems that have been associated with the emergence and persistence of very low fertility.

Patterns of low and lowest-low fertility in Europe

In this paper we conduct descriptive aggregate analyses to revisit the relationship of low and lowest-low period fertility to cohort fertility and key fertility-related behaviour such as leaving the parental home, marriage, and women’s labour force participation. Our analyses show that the cross-country correlations in Europe between total fertility and the total first marriage rate, the proportion of extramarital births, and the labour force participation of women reversed during the period from 1975 to 1999. By the end of the 1990s there was also no longer evidence that divorce levels were negatively associated with fertility levels. We argue that lowest-low fertility has been particularly associated with a ‘falling behind’ of cohort fertility at higher birth orders and later ages. From these analyses we conclude that the emergence of lowest-low fertility during the 1990s was accompanied by a disruption or even a reversal of many well-known relationships that have been used to explain cross-country differences in fertility patterns.

Fertility in Advanced Societies: A Review of Research

This paper provides a review of fertility research in advanced societies, societies in which birth control is the default option. The central aim is to provide a comprehensive review that summarizes how contemporary research has explained ongoing and expected fertility changes across time and space (i.e., cross- and within-country heterogeneity). A secondary aim is to provide an analytical synthesis of the core determinants of fertility, grouping them within the analytical level in which they operate. Determinants are positioned at the individual and/or couple level (micro-level), social relationships and social networks (meso-level); and, by cultural and institutional settings (macro-level). The focus is both on the quantum and on the tempo of fertility, with a particular focus on the postponement of childbearing. The review incorporates both theoretical and empirical contributions, with attention placed on empirically tested research and whether results support or falsify existing theoretical expectations. Attention is also devoted to causality and endogeneity issues. The paper concludes with an outline of the current challenges and opportunities for future research.RésuméCet article présente un aperçu des recherches dans le domaine de la fécondité réalisées dans les sociétés dites avancées, c’est-à-dire les sociétés dans lesquelles le contrôle des naissances est l’option par défaut. L’objectif principal est de fournir une vue d’ensemble complète résumant comment la recherche contemporaine explique les changements de fécondité actuelle et prévue dans le temps et dans l’espace (c’est-à-dire l’hétérogénéité à l’intérieur d’un pays ou entre pays). Un second objectif vise à fournir une synthèse des principaux déterminants de la fécondité en les regroupant par niveau d’analyse dans lequel ils se situent. Les déterminants sont ainsi situés au niveau individuel ou au niveau du couple (niveau micro), au niveau des relations sociales et des réseaux sociaux (niveaux méso) et au niveau des cadres institutionnels et culturels (niveau macro). L’accent est mis tant sur l’intensité que le calendrier de la fécondité avec un intérêt particulier sur le report de la procréation. Cette synthèse de la littérature concerne les recherches tant théoriques qu’empiriques, une attention particulière étant portée à celles qui sont testées empiriquement et dont les résultats confirment ou infirment les théories explicatives existantes. De même nous nous sommes particulièrement intéressés aux problèmes de causalité et d’endogénéité. En conclusion, un tableau des défis actuels et des perspectives futures en matière de recherche est esquissé.

Cohabitation, Marriage, and First Birth: The Interrelationship of Family Formation Events in Spain

In this paper, we investigate (1) the mutualcausal relationship between first unionformation and first childbirth, and (2) theexistence of constant unmeasured determinantsshared by these two events. We argue that thesedeterminants mainly consist of valueorientations that are heterogeneous in thepopulation. We apply event-history techniquesto retrospective survey data on Spain, allowingfor unobserved heterogeneity components whichsimultaneously affect the two processes. Ourfindings confirm the existence of a strongselection effect, which influences both unionformation and first birth. When controlling forthese shared factors, we find that the risk ofconception increases immediately at marriage,and it continues to be high during thefollowing four years. Entry into cohabitation,in contrast, produces a much smaller increasein the relative risk of conception. The effectof conception on union formation isparticularly strong during pregnancy, but itdeclines sharply after delivery.

SHOULD I STAY OR SHOULD I GO? THE IMPACT OF AGE NORMS ON LEAVING HOME*

This article studies the association between social norms and the timing of leaving home. Although largely overlooked by most recent studies on leaving home, life-course theory suggests that age norms and age grading influence life-course decisions in general and leaving home in particular. We use Fishbein and Ajzen’s model of “reasoned behavior” to integrate this strand of research with the more individualistic view that dominates current thinking. Using data from a Dutch panel survey, we use a Cox regression model with a control for sample selection to estimate the association between perceived age norms and the timing of leaving home. We show that perceived opinions of parents are associated with the actual timing of leaving the parental home but that societal norms and friends’ norms concerning the timing of leaving home are not. In addition, the timing of leaving home is also associated with the perceived costs and benefits of leaving home and with the perceived housing market situation.

The analysis of early life courses: Complex descriptions of the transition to adulthood

The quantitative analysis of life courses has to deal with a complex pattern of interrelated events and trajectories. Such a complex pattern needs complex measurement tools, even if only to describe the experience of cohorts. This paper addresses the methodological issue of describing the transition to adulthood from a life course perspective, following an event-based definition. New proposals are developed and traditional approaches are discussed, using Italy as an example. A generalization of survivor functions for the analysis of the temporal relationships between two events is introduced and applied. The paper then deals with the problem of describing the process of transition to adulthood as a whole, making use of the sequence analysis approach with special emphasis on the empirical analyses of the ‘standardization vs individualization’ hypotheses.

Soon, later, or ever? The impact of anomie and social capital on fertility intentions in Bulgaria (2002) and Hungary (2001)

We use survey data from Bulgaria and Hungary to investigate the determinants of whether women intend to have a first or a second child and, if so, whether they intend to have the child within the ensuing 2 years or later. These determinants differ significantly by the order and timing of the intended birth. The variables used include measures of anomie and social capital and these appear to be among the factors that determine both whether to have a child and when. There is some evidence that these measures and economic factors are relatively more important in Bulgaria than in Hungary, and that ideational factors are more important in Hungary, particularly in the case of voluntary childlessness.

Population—The long view

This special issue of Population Studies is the outcome of invitations to a number of scholars in demographic and related sciences to contribute to an exploration of large-scale, long-term, interdisciplinary population problems. In planning the issue, the editors hoped to help put the ‘population’ back into ‘population studies’. They were concerned that the population dimension had become hidden in recent demographic research, which has mostly become focused on micro-level analyses that often do not adequately engage with the relevance of the ‘micro’ for the ‘macro’ level of population behaviour. As Francesco Billari points out in the first paper, we are by no means the first to raise this issue. However, he emphasizes that macro and micro approaches must be seen as complementary for demographic enlightenment, not as hostile rivals. Ultimate questions about how human populations behave in the long term and on the large scale, and what future structures may emerge, will depend upon the actions and interactions of billions of individuals. We need to know more about how the behaviour of actors generates and alters demographic structures at the same time as population structures and interactions affect the behaviour of those actors. This macro/micro divergence is marked in the public realm of politics and the media, as opposed to academia. Public and political concern about population tends to be focused on population change on the large scale: the familiar battleground of population versus resources; rapid growth in poorer countries, population ageing in richer ones; population decline in some countries and in prospect for many others; and all of these interacting under the cloud of climate change. When new data are released about populations, these tend to generate considerable attention and debate. Governments might treat demographic indicators as explicit policy targets, or as reasons to act. Yet in recent years the most striking scientific progress in demography, and most contributions to journals and scientific conferences, have been concerned with the micro scale of demographic processes. Substantial improvements in the availability of individual-level data, especially from longitudinal studies, record linkage, and uniform, multinational surveys have created the potential for much more refined statistical analysis, with rigorous approaches to causal inference and scope for international comparability. That potential has been realized through important innovations and concepts in analytical techniques, such as advanced regression analysis, the recognition of latent variables, event-history analysis, and multi-level modelling. Economics, psychology, sociology, and, more rarely, evolutionary biology have provided theoretical backgrounds and generated hypotheses for micro-level demographic analyses. Maire Ni Bhrolchain’s (1993) iconoclastic paper ‘Period paramount’ disputed the moral and technical superiority of cohort analysis. To some it has seemed that we are now confronted instead with ‘micro paramount’. The life-course approach, based on

Social age deadlines for the childbearing of women and men

BACKGROUND This study examines whether social age deadlines exist for childbearing in women and men, how they vary across countries, whether they are lower than actual biological deadlines and whether they are associated with childbearing at later ages and the availability of assisted reproduction techniques (ARTs). METHODS This study is based on the European Social Survey, Round 3 (2006–2007), which covers 25 countries. Data were gathered on social age deadlines for childbearing in women (21 909 cases) and men (21 239 cases) from samples of representative community-dwelling populations aged 15 and older. RESULTS Social age deadlines for childbearing were perceived more frequently for women than men. These deadlines are often lower than actual biological limits, and for women and men alike: 57.2% of respondents perceived a maternal social age deadline ≤40 years of age; 46.2% of the respondents perceived a paternal social age deadline ≤45 years of age. There is also considerable variability in deadlines across countries, as well as within them. At the country level, the presence of social age deadlines for the childbearing of women was negatively associated with birth rates at advanced ages and the prevalence of ART, and later deadlines were positively associated with these factors. CONCLUSIONS It is important to understand the factors that increase and limit late fertility. While biological factors condition fertility, so do social expectations. These findings provide widespread evidence across Europe that social limits exist alongside biological ones, though both sets of factors are more binding for women.

Little Italy: An Agent-Based Approach to the Estimation of Contact Patterns- Fitting Predicted Matrices to Serological Data

Knowledge of social contact patterns still represents the most critical step for understanding the spread of directly transmitted infections. Data on social contact patterns are, however, expensive to obtain. A major issue is then whether the simulation of synthetic societies might be helpful to reliably reconstruct such data. In this paper, we compute a variety of synthetic age-specific contact matrices through simulation of a simple individual-based model (IBM). The model is informed by Italian Time Use data and routine socio-demographic data (e.g., school and workplace attendance, household structure, etc.). The model is named “Little Italy” because each artificial agent is a clone of a real person. In other words, each agents daily diary is the one observed in a corresponding real individual sampled in the Italian Time Use Survey. We also generated contact matrices from the socio-demographic model underlying the Italian IBM for pandemic prediction. These synthetic matrices are then validated against recently collected Italian serological data for Varicella (VZV) and ParvoVirus (B19). Their performance in fitting sero-profiles are compared with other matrices available for Italy, such as the Polymod matrix. Synthetic matrices show the same qualitative features of the ones estimated from sample surveys: for example, strong assortativeness and the presence of super- and sub-diagonal stripes related to contacts between parents and children. Once validated against serological data, Little Italy matrices fit worse than the Polymod one for VZV, but better than concurrent matrices for B19. This is the first occasion where synthetic contact matrices are systematically compared with real ones, and validated against epidemiological data. The results suggest that simple, carefully designed, synthetic matrices can provide a fruitful complementary approach to questionnaire-based matrices. The paper also supports the idea that, depending on the transmissibility level of the infection, either the number of different contacts, or repeated exposure, may be the key factor for transmission.