Scenario for population projections for small areas: method and application for districts in São Paulo 2000-2010

Abstract

Population projections in Brazil for small areas, such as municipalities, districts, neighborhoods and territorial units, are in ever greater demand for public and private projects and activities. This kind of population data is used to improve planning capabilities at the local level, such as input for urban planning and the allocation of resources for participated planning processes. Most proposed models in the literature are data intensive, based on administrative records maintained by local agencies or governmental offices. Since the coverage and quality of this type of data is very limited in many parts of underdeveloped countries, these models are often useless. This article presents an alternative method of demographic projection for small areas – known as ProjPeq – to produce populational estimates in small areas, a method that is useful when good census data and vital statistics are available. The model presented here is an integrated method for projecting population sizes by using cohort components at the regional level, together with a system of differential equations to divide up the total population based on two parameters – a vegetative factor and a residential attractive factor. The article first presents the integrated model of the demographic component-dynamic system. Secondly, it discusses the importance and use of expert qualitative data on future scenarios in order to project activities. It also presents an application at the district level for the city of São Paulo, comparing results with estimates computed by other techniques.