Accounts and Models for Spatial Demographic Analysis I: Aggregate Population

This paper presents accounts and models which can be used for spatial demographic analysis. It is shown that in any time period there are sixteen different kinds of demographic flows for a two region system. These flows can be represented in an accounting table. Some of the minor flows, involving double or triple demographic events such as a birth followed by a migration, cannot be measured directly from data, and an iterative scheme is offered for the calculation of these flows. In this way a complete set of accounts can be built up from existing data. Two principles of model building using this set of accounts are then discussed. The first uses a simple definition of demographic rates, while the second uses a definition of rates which employs a concept of ‘at-risk’ populations. Procedures are given for calculating these populations. The account building principles are illustrated with a worked example for a three region system: the West Riding of Yorkshire, the rest of England and Wales, and the rest of the world. The results presented in this paper are for aggregate populations. In a subsequent paper equivalent results will be presented for age/sex disaggregated populations.