STATSIM: Statistics Austria's Dynamic Microsimulation Model for Official Population Projections

The cohort-component method is the standard model for producing population projections in official statistics. It is straightforward to compute, requires minimal input data, and is widely recognised by demographers. However, cohort-component projection models are limited in their ability to capture complex demographic processes and provide detailed output for individual-level outcomes. To address these shortcomings, Statistics Austria has developed the dynamic microsimulation model STATSIM for its official national population projection, which was previously computed by the cohort-component method. We have opted for a gradual transition, starting by replicating the results of past cohort-component projections using microsimulation. As a first extension, we have implemented a model of international migration that takes into account the relationship between emigration risk and length of stay, as well as country of birth. By comparing the results of STATSIM's retrospective projections with counterfactual cohort-component projections, we show that STATSIM's projections are more consistent with observed emigration patterns. In the future, STATSIM can be further developed by adding modules for education, employment, health and other socio-economic characteristics.