Sources for mortality data The Human Mortality Database (HMD) was used for the data, supplemented by data from Eurostat for the years and countries for which no data was available in the HMD. For 2015, data from Statistics Netherlands was used as the data pertaining to the Netherlands. The information from these sources is regularly supplemented and is sometimes adjusted with retrospective effect for earlier years. The dataset used, in the form of mortality figures and exposures for both the Netherlands and the total group of West-European countries, can be found on the Association’s website and in total contains more than 100 million cases of death. The effect of these changes on life expectancy is made visible in chapter 8. 6.2 Assumptions of the model Most important assumptions of the model • The development of life expectancy in the Netherlands in the long term is based on the observed development of life expectancies in European countries with GDP above the European GDP average. • No separate cohort effects (including the effects of smoking behaviour) have been included because this increases the complexity of the model considerably. • For ages over 90, the mortality probabilities are extrapolated using the Kannistö method. • Only publicly available data have been used. Projection Model AG2014 is the point of departure The point of departure for the present model is the stochastic model used for Projection Table AG2014. This is a multi-population mortality model, as proposed by Lee and Li, with a two-stage approach to estimating the necessary parameters (see Appendix A). In addition, the European trend is estimated for each sex using the Lee-Carter model. The Lee-Carter mortality model is then used again to reflect the deviation of the Netherlands from the common trend. By combining the data from different, but comparable countries, a more robust model emerges with more stable trends and a smaller sensitivity to the calibration period used. The model is based on four stochastic processes: a) the development of mortality in Europe for men; b) the development of the deviation of mortality in the Netherlands relative to Europe for men; c) the development of mortality in Europe for women; d) the development of the deviation of mortality in the Netherlands relative to Europe for women; For developments a) and c) in Europe, a random-walk-with-drift model is used. For developments b) and d) in the Netherlands, a first-order auto-regressive process without a constant is used. The latter means that the development of mortality in the Netherlands is expected to follow the European trend in time. The four processes are estimated jointly in order also to estimate the correlations between the various processes. The joint implementation of this final step is a change relative to the estimation procedure used for Projection Table AG2014. For mortality in Europe, data up to and including 2014 is available and for mortality in the Netherlands data is available up to and including 2015. To estimate the four stochastic Projection Table AG2016 Mortality data and assumptions of the model 14
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