Regional Population Project Models and Accounting Methods

The paper outlines how population accounting models may be used in a variety of ways. The field of interest is first defined in terms of a map, the dimensions of which are a pure-applied scale and a scale of modelling sequence. The various modes of use of regional population projection models are described. The modes include naive, simple, unconstrained, constrained, with incomplete data, with alternative calibrations, simulation and testing mode. The algebraic notation of population accounts is specified, the conceptual framework of population accounts is developed, and a multi-regions projection model is built based on population accounts. Key issues in projection model design are discussed and four general principles of model design suggested, namely, system closure, time variable rates, separation of the component processes, and matching of populations at risk in the model and input rates. A case study in multiregional population projection is then described. The final sections of the paper discuss the choices involved when population accounts matrices are constrained and how the best method of accounts construction in a particular situation might be selected.