Demography

The Population projections are a key parameter for studying the impact of ageing, an issue of growing concern for policymakers in Belgium and other European countries.

Population ageing, or the growing ratio of elderly people in the population, is primarily the result of both a decreasing fertility rate and the sustained prolongation of life expectancy. This evolution takes its toll on the public budget. The changes in the demographic structure lead to a decrease in the working-age population likely to pay social contributions and taxes on the one hand, and increase the number of elderly people who receive public pensions and a larger amount of health care on the other hand.

The essential parameters determining population should therefore be studied carefully: fertility, probability of death and decision to migrate within the country, to emigrate or to immigrate.

In addition to being one of the components of the demographic model, the projection of mortality rates is necessary because of the law of 28 April 2003 on supplementary pensions. The law provides that the FSMA bases its actualisation rules for converting capital to interest on the FPB’s prospective mortality tables.

Studying the population from the perspective of ‘households’ is also very useful for various social aspects (e.g. increase in single-parent families – the parent often being a single woman – households composed of an older person who might be confronted with poverty or insufficient support) and economic aspects (impact on housing, transport, mobility, consumption, taxation, etc.) of life. Within that framework and in line with the population projects, the FPB also draws up household projections.

Methods and tools

For demographic projections, three models are used:

• A model used for the long-term population projections and which is based on the component method. Thus, it constitutes an iterative model which uses fertility, mortality and (national and international) migration assumptions to calculate the population on 31 December of a specific year, using the latest observations by age, gender and nationality. This methodology allows assumptions for each component to be defined and forms an integrated part of the demographic model. The model simulates the long-term population (01/01/2061) by age and gender for each district.
• The model used for the household projections is a static model which breaks down the population projections by age, gender and district, based on the rate at which a position within the household occurs. The positions are defined by the LIPRO typology (Lifestyle Projections), which focuses on the factual situation of individuals and not on their legal situation. The position occurrence rates are not constant over the projection period, but are extrapolated by age, gender and district based on the (recent) evolution, with a saturation effect in the long term.
• The model used to calculate the prospective mortality tables is based on the population observations (births, deaths, population). It assesses the future curve of mortality rates by age and gender based on a specific model and allows prospective mortality tables to be generated which serve as a hypothesis for the population projections.