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Discontinuities in Household and Family Formation

Periodic Reporting for period 4 - DisCont (Discontinuities in Household and Family Formation)

Reporting period: 2021-08-01 to 2022-07-31

Demographic change is one of the great challenges of our time. Changes in household, family, and fertility are among its key drivers. Discovering and explaining the direction and speed of change in household, family, and fertility, and the causal factors that underlie these changes, is essential both to understand the current situation and to provide scientific evidence on our demographic future and the information in support of policy decisions. Both at the EU level and at the global level, with UN Agenda 2030 putting Sustainable Development Goals in an explicit framework, demography has been put at the center of the policy agenda. For the first time, the European Commission Presidency has appointed a Commissioner and Vice-President for "Democracy and Demography".
The DisCont ERC-ADG project has studied the impact of important and fast societal-level changes ("discontinuities"), and in particular the digital revolution and the Great Recession, on household, family and fertility in post-industrial contemporary societies and at the global level.

In post-industrial contemporary societies, population change is often believed to occur in a relatively smooth, orderly and inertial way. In the past, before the so-called "demographic transition", populations were periodically hit by sudden crises and subsequent recoveries. The demographic transition, with secular declines in mortality and fertility, is usually seen as bringing smoothness in population change, continuity rather than discontinuity. Research in demography has therefore become acquainted with this smoothness. For instance, demographic change has become among the few developments in our societies that we tend to feel confident in forecasting over the long term.

Through a coordinated series of theoretically-grounded empirical studies, drawing on a comparative perspective, the overall objective of DisCont has been to challenge conventional wisdom that population change, in a post-demographic-transition world, happens in a smooth, orderly, and inertial way. The main focus of the project has been on two post-Millennium discontinuities, the Great Recession and the digital revolution, and their effect on demographic change, and in particular on household, family, and fertility change. During the course of the project, the Covid-19 pandemic has provided an additional and fundamental instance of a discontinuity with an impact on population change. In addition to substantial contributionsDIsCont also contributed to advancing the methodological tools that are used to study demographic change, using new methods for the analysis of existing data and newly available data to address scientific issues.
The DisCont project has covered all areas that were originally planned, with some expansion towards related and promising avenues of research, and additional results on the discontinuity induced by the Covid-19 pandemic during the final part of the project.
In terms of scientific impact (see list of Output in the 'Publications' section), publications span several disciplines, with general science journals, and top journals in the areas of Demography, Economics, Sociology, Statistics and Psychology, as well as conference proceedings in Computer Science.

Example of major scientific achievements include:

- Francesco C. Billari,"Demography: Fast and Slow", Population and Development Review, 2022. This article has advanced the field of population studies by pointing to the distinction between fast and slow population change, importing measures of population turnover, and introducing an indicator on the role of migration, to the global study of population change.

- Francesco C. Billari, Osea Giuntella, Luca Stella, "Does broadband Internet affect fertility?", Population Studies, 2019. This article has shown for the first time that the digital revolution, and in particular the diffusion of broadband Internet, can act in favour of fertility in low fertility settings, albeit with important social stratification differences.

- Osea Giuntella, Lorenzo Rotunno, Luca Stella, "Globalization, Fertility, and Marital Behavior in a Lowest-Low Fertility Setting ", Demography, 2022. This article has documented, for the first time, the impact of import competition, as a key element of globalization, in low fertility settings.

- Valentina Rotondi, Ridhi Kashyap, Luca Maria Pesando, Simone Spinelli, Francesco C. Billari "Leveraging mobile phones to attain sustainable development", Proceedings of the National Academy of Sciences of the United States of America, 2020. This article has documented, for the first time at the global level, the broadly positive impact of the digital revolution on a set of sustainable development outcomes related to population,through a focus on the diffusion of mobile phones.

In terms of methodological developments, researchers based at the University of Oxford, with collaboration from other DisCont members, have mainly worked on statistical methods for the study of population change, and in particular for the
detection of discontinuities. In addition and to support these methodological developments, DisCont members contributed to the development of publicly available software package (called
'apc', available at for both the R statistical language and Python. The dissemination of this methodological work is
in line with best practices in the field. Moreover, the project has worked, in collaboration with leading scholars in the field, in the innovative use of 'digital breadcrumbs' data (i.e. data generated on the Internet) for the study of demographic behavior.

In this area, a key example of scientific achievement is:

- Jonas Harnau, Bent Nielsen, "Over-Dispersed Age-Period-Cohort Models", Journal of the American Statistical Association, 2018. This article has introduced a new class of Age-Period-Cohort models without measures of exposure, which is applicable in many fields and areas.
We believe that DisCont has contributed to modifying the state of the art, in particular for what concerns the effects of the digital revolution on household, family, and fertility. We expect this to expand and consolidate even after the end of the project, with additional scientific output providing additional evidence, in terms of both geographical reach and behaviours studies. The additional availability of data, and time spent since the Great Recession and the beginning of the digital revolution, as well as Covid-19, will provide new opportunities. Moreover, as DisCont researchers have formed a broader network, with collaborations expected to increase in the future. For what concerns methodological developments, we expect to advance further Age-Period-Cohort models and to make these advancements accessible to other scholars.

There has been a careful attention on dissemination activities towards the general public, also thanks to the support of the efficient Press Office of Bocconi university. One leading example is the short Masterclass video, in collaboration with Financial Times, which features the partecipation of the PI and of the Vice-President of the European Commission for Democracy and Demography, Ms. Dubravka Šuica, available at:

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