To understand the relative contributions of demographic components (fertility, mortality, migration) to changes in populations’ age structures, demographers have made extensive use of the variable-r model. Whether the current trends in global population aging are predominantly driven by fertility (Lee-&-Zhou 2017, revisers) or mortality (Preston-&-Stokes 2012, revisionists) is still a matter of debate. We introduce a modified version of the variable-r model designed to answer a simple question: is the growth rate at a given age a consequence of the growth rate at some younger age, or due to progress in reducing mortality between the two ages? These modifications result in substantially shorter requirements for historical data, allowing our method to be applied in a broader set of contexts and populations. Illustrations for Australia and other countries/regions and age groups are explored: for example, the observed growth of centenarians results from high growth rates of 80-year-olds, and from time-reductions in cohort mortality between ages 80 and 100. At younger ages time-changes in migration between the different ages also influence the population growth rates.
Vladimir Canudas-Romo is an ANU-demographer with an interest in mathematical demography, particularly on the development of new demographic measures. He was awarded his PhD in 2003 at the Max Planck Institute for Demographic Research, Germany, and the University of Groningen, the Netherlands. Since his PhD he has worked in six universities: In the USA, he worked at Pennsylvania State University, the University of California Berkeley and Johns Hopkins Bloomberg School of Public Health. In Denmark he worked at the University of Copenhagen and the University of Southern Denmark. Finally, in September 2017, he joined the School of Demography at the Australian National University as Associate Professor. As a result of all these movements, he has built a strong international collaborative network with top researchers. He has been awarded prestigious and highly competitive grants (e.g. the European Research Council) and has carried out research for the World Bank and industry (e.g. American Insurance Group). He has mentored masters and PhD students and enjoys an international reputation for his passion on demographic topics, particularly those related to mathematical demography.