Demographic ageing: the rigidity of conventional metrics and the need for their revision

This article aims to discuss the scope and value of the conventional metrics used to assess and compare levels of ageing between different populations. The age brackets for classifying if the population is ageing or aged are typically based on chronological age and are very close to the stages of the economic tripartite life cycle: the school/education phase; the labour market participation phase; the retirement phase. Those conventional metrics produce distortions in capturing the levels of demographic ageing. If the change in the age structure is rooted in social development, not in a social crisis, having more people in older ages should be related to that. Living longer, on average, does not only mean living more years but also a change in people's social profile, which the usual metrics for measuring ageing do not capture. Because of the central place that demographic ageing occupies in the framework of social, political and scientific reflection on the present and future of societies, Demographic Science should contribute with new metrics reflecting the real social improvements in populations age structures. This reflection supports the need to undertake a critical analysis of the way demographic ageing has usually been presented; stresses the need to advance ageing metrics that match societies' development by considering the life expectancy; and presents a new indicator for measurement demographic ageing that compares what we observe with what we can expect from the age structure at any given mortality level.