Joop de Beer

Overcoming the Problems of Inconsistent International Migration data: A New Method Applied to Flows in Europe

Due to differences in definitions and measurement methods, cross-country comparisons of international migration patterns are difficult and confusing. Emigration numbers reported by sending countries tend to differ from the corresponding immigration numbers reported by receiving countries. In this paper, a methodology is presented to achieve harmonised estimates of migration flows benchmarked to a specific definition of duration. This methodology accounts for both differences in definitions and the effects of measurement error due to, for example, under reporting and sampling fluctuations. More specifically, the differences between the two sets of reported data are overcome by estimating a set of adjustment factors for each country’s immigration and emigration data. The adjusted data take into account any special cases where the origin–destination patterns do not match the overall patterns. The new method for harmonising migration flows that we present is based on earlier efforts by Poulain (European Journal of Population, 9(4): 353–381 1993, Working Paper 12, joint ECE-Eurostat Work Session on Migration Statistics, Geneva, Switzerland 1999) and is illustrated for movements between 19 European countries from 2002 to 2007. The results represent a reliable and consistent set of international migration flows that can be used for understanding recent changes in migration patterns, as inputs into population projections and for developing evidence-based migration policies.RésuméLes comparaisons entre pays des caractéristiques des migrations internationales s’avèrent difficiles et confuses du fait des différences de définitions et de méthodes de mesure. Les chiffres de l’émigration fournis par les pays d’origine des migrants différent souvent des chiffres recueillis par les pays d’accueil. Cet article propose une méthode destinée à rendre cohérentes les estimations des flux migratoires en se référant à une définition spécifique de la durée de séjour. Cette méthodologie tient compte à la fois des différences de définitions et des conséquences des erreurs de mesure dues, par exemple, au sous-enregistrement et aux fluctuations de l’échantillonage. Plus spécifiquement, les différences entre les deux séries de données rapportées sont corrigées en estimant un ensemble de facteurs d’ajustement des données pour chaque pays d’immigration et d’émigration. Les données ajustées tiennent compte de tous les cas particuliers dans lesquels les schémas origine–destination ne correspondent pas aux schémas généraux. Cette nouvelle méthode d’harmonisation des données des flux migratoires, basée sur les travaux antérieurs de Poulain (1993, 1999), est appliquée aux mouvements migratoires entre 19 pays européens de 2002 à 2007. Les résultats présentent des séries fiables et cohérentes de flux migratoires internationaux qui peuvent être utilisées pour comprendre les changements récents dans les schémas migratoires, pour réaliser des projections de population, et pour développer des politiques migratoires à partir d’informations plus sûres.

Maximum human lifespan may increase to 125 years

Brief Communications Arising: arising from X. Dong, B. Milholland & J. Vijg Nature 538, 257–259 (2016); doi:10.1038/nature19793. Comments by: Beer, J.A.A. de, Bardoutsos, A. & Janssen, F. (2017).

A new parametric model to assess delay and compression of mortality

BackgroundA decrease in mortality across all ages causes a shift of the age pattern of mortality, or mortality delay, while differences in the rate of decrease across ages cause a change in the shape of the age-at-death distribution, mortality compression or expansion. Evidence exists for both compression and delay of mortality. Existing parametric models to describe the full age pattern of mortality are not able to capture mortality delay versus mortality compression. More recent models that assess delay versus compression mostly focused on the adult or old ages alone and did not distinguish mortality compression below and above the modal age at death, although they represent different mechanisms.MethodsThis paper presents a new parametric model that describes the full age pattern of mortality and assesses compression – at different stages of life – and delay of mortality: the CoDe model. The model includes 10 parameters, of which five are constant over time. The five time-varying parameters reflect delay of mortality and compression of mortality in infancy, adolescence, young adulthood, late adulthood, and old age. The model describes infant and background mortality by two simple functions, uses a mixed logistic model with different slopes in adult, middle, and old age, and includes the modal age at death as a parameter to account for the delay in mortality.ResultsApplying the CoDe model to age-specific probabilities of death for Japanese, French, American, and Danish men and women between 1950 and 2010 showed a very good fit of the full age pattern of mortality. Delay of mortality explained about two-thirds of the increase in life expectancy at birth, whereas compression of mortality due to mortality declines in young age explained about one-third. No strong compression of mortality in late adulthood age was observed. Mortality compression in old age has had a small negative impact on life expectancy.ConclusionsThe CoDe model proved a valid instrument for describing the full age pattern of mortality and for disentangling the effects of mortality delay and compression – at different stages of life – on the increase in life expectancy.

Decomposition of regional convergence in population aging across Europe

In the face of rapidly aging population, decreasing regional inequalities in population composition is one of the regional cohesion goals of the European Union. To our knowledge, no explicit quantification of the changes in regional population aging differentiation exist. We investigate how regional differences in population aging developed over the last decade and how they are likely to evolve in the coming three decades, and we examine how demographic components of population growth contribute to the process. We use the beta-convergence approach to test whether regions are moving towards a common level of population aging. The change in population composition is decomposed into the separate effects of changes in the size of the non-working-age population and of the working-age population. The latter changes are further decomposed into the effects of cohort turnover, migration at working ages, and mortality at working ages. European Nomenclature of Territorial Units for Statistics (NUTS)-2 regions experienced notable convergence in population aging during the period 2003–2012 and are expected to experience further convergence in the coming three decades. Convergence in aging mainly depends on changes in the population structure of East-European regions. Cohort turnover plays the major role in promoting convergence. Differences in mortality at working ages, though quite moderate themselves, have a significant cumulative effect. The projections show that when it is assumed that net migration flows at working ages are converging across European regions, this will not contribute to convergence of population aging. The beta-convergence approach proves useful to examine regional variations in population aging across Europe.

Disentangling rectangularization and life span extension with the moving rectangle method

PURPOSE The moving rectangle method is used to disentangle the contributions of rectangularization and life span extension to the increase in life expectancy. It requires the choice of an endpoint of the survival curve that approaches the maximum age at death. We examined the effect of choosing different end points on the outcomes of this method. METHODS For five developed countries, survival curves from age 50 years were constructed per calendar year from 1922 onward. Survival values of 0.1, 0.01, and 0.001 were chosen as end points of the survival curve, and the contributions of rectangularization and life span extension to the increase in life expectancy were calculated using the moving rectangle method. RESULTS The choice of different survival values as end points profoundly influenced the estimated contributions of rectangularization and life span extension to the increase in life expectancy. When choosing 0.001, rectangularization contributed most years, whereas when choosing 0.1, life span extension contributed most years. CONCLUSIONS When the moving rectangle method is used to estimate the contributions of rectangularization and life span extension to the increase in life expectancy, its outcomes depend on the choice of the endpoint of the survival curve.

Overcoming the Problems of Inconsistent International Migration data

Due to differences in definitions and measurement methods, cross-country comparisons of international migration patterns are difficult and confusing. Emigration numbers reported by sending countries tend to differ from the corresponding immigration numbers reported by receiving countries. In this paper, a methodology is presented to achieve harmonised estimates of migration flows benchmarked to a specific definition of duration. This methodology accounts for both differences in definitions and the effects of measurement error due to, for example, under reporting and sampling fluctuations. More specifically, the differences between the two sets of reported data are overcome by estimating a set of adjustment factors for each country’s immigration and emigration data. The adjusted data take into account any special cases where the origin–destination patterns do not match the overall patterns. The new method for harmonising migration flows that we present is based on earlier efforts by Poulain (European Journal of Population, 9(4): 353–381 1993, Working Paper 12, joint ECE-Eurostat Work Session on Migration Statistics, Geneva, Switzerland 1999) and is illustrated for movements between 19 European countries from 2002 to 2007. The results represent a reliable and consistent set of international migration flows that can be used for understanding recent changes in migration patterns, as inputs into population projections and for developing evidence-based migration policies.RésuméLes comparaisons entre pays des caractéristiques des migrations internationales s’avèrent difficiles et confuses du fait des différences de définitions et de méthodes de mesure. Les chiffres de l’émigration fournis par les pays d’origine des migrants différent souvent des chiffres recueillis par les pays d’accueil. Cet article propose une méthode destinée à rendre cohérentes les estimations des flux migratoires en se référant à une définition spécifique de la durée de séjour. Cette méthodologie tient compte à la fois des différences de définitions et des conséquences des erreurs de mesure dues, par exemple, au sous-enregistrement et aux fluctuations de l’échantillonage. Plus spécifiquement, les différences entre les deux séries de données rapportées sont corrigées en estimant un ensemble de facteurs d’ajustement des données pour chaque pays d’immigration et d’émigration. Les données ajustées tiennent compte de tous les cas particuliers dans lesquels les schémas origine–destination ne correspondent pas aux schémas généraux. Cette nouvelle méthode d’harmonisation des données des flux migratoires, basée sur les travaux antérieurs de Poulain (1993, 1999), est appliquée aux mouvements migratoires entre 19 pays européens de 2002 à 2007. Les résultats présentent des séries fiables et cohérentes de flux migratoires internationaux qui peuvent être utilisées pour comprendre les changements récents dans les schémas migratoires, pour réaliser des projections de population, et pour développer des politiques migratoires à partir d’informations plus sûres.