Sub national population projection: how to deal with heterogeneity?

Samir K.C., Wittgenstein Centre (IIASA, VID/ÖAW, WU)
Markus Speringer, Wittgenstein Centre (IIASA, VID/ÖAW, WU)

This paper describes our approach to establish a method to downscale population data, from higher spatial units to smaller administrative units or grid level to conduct sub national population projections. Population projections are needed at the national and sub-national level even down to much smaller grid levels. Projections are simply a result of assumptions about the future, if the assumptions do not hold right then the projection is wrong. It is a common knowledge that the discrepancies between the projected population and the actual depends upon the level of aggregation or the size of the population. There are several methods of sub-national population projections and most of them do not consider demographic heterogeneity within a country. We propose to further investigate current practices and plan to propose a projection model based demographic tools that takes account the demographic heterogeneity and apply it to four countries: Austria, Nepal, Mexico or Turkey. The significance of this work will be most probably on the quality of the projections mainly due to the inclusion of demographics methods and science.