Les projections démographiques. Principaux mécanismes et retour sur l'expérience française
Demographic projections are generally considered as more robust than all other kinds of socio-economic forecasts. But doubts are sometimes cast on their relevance, especially when strong revisions of previous projections are proposed, as done by insee in 2006. The purpose of this paper is to come back on the scope and limits of these projections. We first recall their methodology and a few elementary results concerning population dynamics, with a particular emphasis on how fertility and migration codetermine the long run demographic growth rate. We then use the retrospective experience of projections conducted at insee since 1964 to identify where are the major weaknesses of these projections but also their main strengths. This retrospective examination shows strong revisions concerning trends for total population or for the population in working ages, but without any questioning of the global ageing trend. We explain this result by isolating a concept of trend ageing due to the pure role of life expectancy. Changes in fertility levels or in migration flows lead to deviations from this trend that, in the French case, remain second order and more or less temporary. We conclude by outlining that the uncertainty that affects projections does not make them irrelevant for decision making. Decision under uncertainty is the common lot for most of our problems of collective or individual choice. The right answer to this uncertainty is to set in appropriate adjustment rules to deal with revisions that unavoidably stem from this uncertainty. Classification JEL�: J10, J11.
When requesting a correction, please mention this item's handle: RePEc:cai:recosp:reco_595_0893. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Jean-Baptiste de Vathaire)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.