Demography

Research finds that hot weather causes a fall in birth rates nine months later. Evidence suggests that this decline in births is due to hot weather harming reproductive health around the time of conception. Birth rates only partially rebound after the initial decline. Moreover, the rebound shifts births toward summer months, harming infant health by increasing third trimester exposure to hot weather. Worse infant health raises health care costs in the short term as well as reducing labor productivity in the longer term, possibly due to lasting physiological harm from the early life injury.

Demographic factors in migrant-sending countries can influence international migration flows. But when migrants move across borders, they can also influence the pace of demographic transition in their countries of origin. This is because migrants, who predominantly move on a temporary basis, encounter new fertility norms in their host countries and then bring them back home. These new fertility norms can be higher or lower than those in their country of origin. So the new fertility norms that result from migration flows can either accelerate or slow down a demographic transition in migrant-sending countries.

Population aging in many developed countries has motivated some governments to provide wage subsidies to employers for hiring or retaining older workers. The subsidies are intended to compensate for the gap between the pay and productivity of older workers, which may discourage their hiring. A number of empirical studies have investigated how wage subsidies influence employers’ hiring and employment decisions and whether the subsidies are likely to be efficient. To which groups subsidies should be targeted and how the wage subsidy programs interact with incentives for early retirement are open questions.

The rise in the average age of women bearing their first child is a well-established demographic trend in recent decades. Postponed childbearing can have important consequences for the mothers and, at a macro level, for the country in which they live. Research has primarily focused on the effect postponing fertility has on mothers’ labor market outcomes and on the total number of children a woman has in her lifetime. Most research finds that postponing the first birth raises a mother's labor force participation and wages but may have negative effects on overall fertility, especially in the absence of supportive family-friendly policies.

The Great Recession that began in 2008–2009 dramatically increased youth unemployment. But did it have long-lasting, adverse effects on the careers of youths? Are cohorts that graduate during a recession doomed to fall permanently behind those that graduate at other times? Are the impacts different for low- and high-educated individuals? If recessions impose penalties that persist over time, then more government outlays are justified to stabilize economic activity. Scientific evidence from a variety of countries shows that rigid labor markets can reinforce the persistence of these setbacks, which has important policy implications.

As migration rates increase across the world, the choice of whether to retire in the host or home country is becoming a key decision for up to 15% of the world’s population, and this proportion is growing rapidly. Large waves of immigrants who re-settled in the second half of the 20th century are now beginning to retire. Although immigrants’ location choice at retirement is an area that has barely been studied, this decision has crucial implications for health care and social protection expenditures, both in host and origin countries.

For decades, pension systems were based on the rising revenue generated by an expanding population (the so-called demographic dividend). As changes in fertility and longevity created new population structures, however, the dividend disappeared, but pension systems failed to adapt. They are kept solvent by increasing redistributions from the shrinking working-age population to retirees. A simple and transparent structure and individualization of pension system participation are the key preconditions for an intergenerationally just old-age security system.

The importance of benefit portability is increasing in line with the growing number of migrants wishing to bring acquired social rights from their host country back to their country of residence. Failing to enable such portability risks impeding international labor mobility or jeopardizing individuals’ ability to manage risk across their life cycle. Various instruments may establish portability. But which instrument works best and under what circumstances is not yet well-explored.