Age waves of baby boom and baby bust generations through arithmetic and geometric coefficients of population ageing in Serbia

Abstract

Age waves is theoretical concept that take into account the importance of disordered cohort flows, mainly as by-product of demographic transition (fluctuating fertility and improved survival), but also external factors (especially wars). The primary age wave as a consequence of high births after the Second World War in Serbia did not remain an isolated phenomenon, but created a secondary cohort wave although the fertility indicators were declining, which is visible as the thickening of the pyramid base in 1981 due to the absolute increase in births. Cohort "tide" has influenced the shape of the pyramid to longer retain the properties of the stationary type because the baby boom generation reproduced the "echo" generation, which is a counterbalance to extreme demographic aging as the baby boom generation entered the contingent of the old population. A cohort analysis of the elderly population shows that the declining share of the elderly in a certain age group is typical for cohorts born during turbulent times, most often wars, while cohorts born afterwards form more numerous generations. A half-century characteristic of the Serbian population is an absolute increase of people older than 65, but it does not automatically mean an adequate increase in the relative share of the elderly because it depends on the number of other age groups and their cohort trajectories. The methodological tool that can valorize heterogeneity of the old population is important for societies with past oscillations in fertility and migratory movements. In this study, the usefulness of the arithmetic and geometric coefficients of aging was tested on the example of baby boom and baby bust generations and their position in the old population, revealing periods when rejuvenation or aging of the old has dominated.