Who is absent from school when? An optimal matching analysis of within-year variation in the timing of school absences

Although school absenteeism trajectories can be studied through various parameters and dimensions, such as the amount of school absenteeism, sequence, and timing, most studies have only focused on changes in the amount of school absenteeism. However, when investigating the nature of school absenteeism, an analysis cannot be restricted to just changes in the amount of school absenteeism. In this article, I show how applying optimal matching on time-stamped half days of missed school (n = 6260) enables researchers, policy makers, and school professionals to uncover socio-temporal regularities in trajectories of non-attendance (i.e., the degree to which groups of pupils are absent at the same time and in the same rhythm within a given school year). Results indicated that students fall into five types of trajectories, and that these are highly predictive of student's examination results at the end of the school year. In the Discussion, I elaborate on the implications of these findings.

Couple Formation is Prolonged not Postponed. New Paths to Union Formation in Contemporary France

In France, as in other European countries, the age at first cohabiting union has risen over the past decades, as a result of longer school enrolment, structural economic changes, and new family norms. While the median age at first co-resident couple was 23.8 for men born in France in the beginning of the 1950s, it was 26.0 among the generation born in the beginning of the 1970s. This tendency is often referred to as a postponement of couple formation and as a part of a broader delay in the transition to adulthood. This article argues, on the contrary, that couple formation has not been postponed but prolonged. In fact, age at first couple formation has remained stable across generations born since the mid-twentieth century in France. Starting from there, we take on a biographical approach to examine the nature, duration, and articulation of the successive stages that make up young people's conjugal trajectories in France. What are the different pathways into couple life, and how have these changed over time? In order to answer these questions, we use optimal matching methods to identify ideal typical trajectories and then logistic regressions in order to see how these relate to generational differences as well as sociodemographic characteristics. We observe three traditional, three timeless and five new paths to couple life. The main historical change is the increasingly gradual nature of union formation, a trend that reflects a dual pattern. First, unions are progressively institutionalized: the time laps between different relationship stages, such as "going out," "settling in," and eventually marrying, have expanded. Second, young people increasingly experience several relationships during youth: the different steps of couple formation are taken with different partners. We conclude that couple formation is not delayed per se; it is rather the material and institutional formalization of unions that is put off for the future. We discuss the scientific and methodological implications of this finding.

The vulnerability of shellfish farmers to HAB events: An optimal matching analysis of closure decrees

Harmful Algal Blooms (HAB) events may have serious economic consequences for shellfish farmers. When toxic algae blooms threaten human health, public authorities may decide to shut down the farming business for a while, i.e. ranging from a few days to several weeks or months, according to the severity of risks. The impact of closures being temporally and spatially distributed, shellfish farmers can avoid the risky zones or develop adaptive strategies to mitigate the economic consequences and therefore reduce significantly their business sensitivity to HABs. A sequential approach by optimal matching analysis is applied to an original data set of shellfish area closure decrees between April 2004 and December 2018 in Southern Brittany and Pays de la Loire (France) to build a typology of 79 aquaculture zones affected by various HAB and microbiological hazards (ASP, DSP, Norovirus, E. Coli, oil spills). The hypothesis is that the degree of exposure to the HAB hazard assessed by zonal closures may not be correlated to the level of sensitivity revealed by the economic results of the shellfish farming industry which can develop avoidance strategies.

Individualization, opportunity and jeopardy in American women's work and family lives: a multi-state sequence analysis

Life course sociologists are increasingly concerned with how the general character of biographies is transformed over historical time--and with what this means for individual life chances. The individualization thesis, which contends that contemporary biographies are less predictable, less orderly and less collectively determined than were those lived before the middle of the 20th century, suggests that life courses have become both more internally dynamic and more diverse across individuals. Whether these changes reflect expanding opportunities or increasing jeopardy is a matter of some debate. We examine these questions using data on the employment, marital and parental histories, over the ages of 25-49, for five birth cohorts of American women (N=7150). Our results show that biographical change has been characterized more by growing differences between women than by increasing complexity within individual women's lives. Whether the mounting diversity of work and family life paths reflects, on balance, expanding opportunities or increasing jeopardy depends very much on the social advantages and disadvantages women possessed as they entered their prime working and childrearing years.