Zusammenfassung (übersetzt):
The population projections elaborated in this work sought to fulfi ll the objective of producing quantitative inputs that help in the analysis and simulations of the macroeconomic impacts of different proposals for reforming the social security system in Brazil. Hence the need to consider, in these projections, the period from 2010 to 2100, a longer time limit than is normally used in exercises of this nature. Furthermore, the variables sex and age groups were considered for fi ve years, in order to obtain the structure and composition of the Brazilian population in the medium and long term, and thus verify the demographic impact on the social security system. It is known that projection exercises involve complex tasks, mainly because human populations are very dynamic and their dynamism is affected by conjunctural effects that are often not foreseen in the projections. However, it is possible to obtain very reasonable population projections with the elaboration of coherent hypotheses and with the application of techniques and the use of appropriate data. The offi cial population projections carried out by the Brazilian Institute of Geography and Statistics (IBGE) were taken as a reference base for the development of the exercise presented here, as they are recognized, notably, for the methodological rigor applied. Population projections for Brazil were prepared considering three distinct scenarios: IBGE/Ipea scenario, population shock scenario and constant fertility scenario. In each of these scenarios, specifi c hypotheses were adopted and their own techniques were applied. This resulted in three possible population projections that differed in terms of composition by sex and age groups and that could have different effects on the social security system.